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"The number of downloads grew at a sluggish pace at first because the app was designed so that just one calculator is displayed on the smartphone's vertical screen mode, while two are shown only when the screen is rotated on its side. So, many users only thought it was a regular calculator."
So is this significantly better than just using store and recall?
In my opinion it is, because I don't need to recall what I recall.
When I need to recall what I recall, I just hit [MR].
Which causes you to then lose what you have typed in the screen already.

TBH, these semi-snarky "How is this any different from MS/MR?" responses are like "Why should a CPU ever need more than 2 registers?" to me.

But then, why should my phone screen be limited to only 2 calculators?
Instead of more calculators, all you really need is just better design. See above.
Which causes you to then lose what you have typed in the screen already.

Then hit [MX] instead. Problem solved with 1 button instead of a whole extra calculator.

"Why should a CPU ever need more than 2 registers?"

The question in this case is "Why should a calculator only have 2 registers". This approach doesn't scale beyond 2 numbers?

Personally, I prefer RPN where I have a whole stack to work with.

What is the [MX] button? I don't think I've ever seen that on a calculator.

TBH, though, this is still kind of like arguing that people should never need GUIs because you can do everything on the command line. There is a pretty obvious, fundamental difference being able to see everything on the screen at the same time, vs having to remember what you stored in memory (and what calculations went into it).

As for RPN, while I agree most people are never taught RPN.

[MX] = Memory Exchange --- Swap display and memory

A better, more intuitive solution than any of the above with available screen real estate is a history tape of prior resultants created automatically.

Multiple prior resultants (not just 2) always available to view --- no action required.

To recall a number from the tape into the active accumulator for further manipulation, simply click the number.

To remove a number from the tape, click and drag right or left. To reorder, click and drag up or down.

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in terms of ease of use and visibility yes I would say this is more than significantly better.
It’s only $3. How much better does it need to be to be worth $3?
What happens if I am working with 3 or 4 different values?

This duplicate calculator method doesn't scale too well. A history tape is a better option --- just as intuitative but more capable/flexible.

Are you looking for people to tell you this is what you should be using?

If it doesn't work for you, then use something else.

Then you start approaching spreadsheet territory.
With a history tape calculator, you can easily and intuitively juggle 5 or 6 different numbers --- not just 2.
So what history tape calculator do you use on iOS?
None --- I don't use iOS. Inferior software support is one of the reasons why.

These are readily available on other platforms. The Android default calculator supports this by simply pulling the display down to reveal "history". And there are a bunch of other apps with even more advanced features and functionality.

Personally, I use an RPN calculator where I have a whole stack to work with --- not just 2 numbers.

absolutely
The base calculator on iPhone is pretty horrible in my experience, but I guess I'm not the target audience. I've really enjoyed eduCalc Classic. It has graphing functionality plus a "guess the function" game based off graph + table which has become my go to plane activity. The unit converter is super useful too.
What is even worse is the ipad has no default calculator (or weather app).

I was so surprised it did not exist I ported the iphone app as a pwa using Typescript and wrote about it here.

https://mejuto.co/the-ipad-did-not-have-a-calculator-so-i-po...

iPad finally [0] has a default weather app in iPadOS 16, but still no calculator.

[0]: https://www.theverge.com/2022/6/6/23156804/apple-weather-app...

What’s even harder to understand is why there isn’t a good 3rd party iPad calculator app. This doesn’t feel like a difficult problem to solve, and yet here we without an intuitive, good looking calculator for the iPad.
just wanted to link Craig's response to why there isnt a calculator for iPad: https://youtu.be/Q2aaCDNjWEg?t=900
Yea yea yea. That’s why I said 3rd party. I know they long ago decided not to make an app and have given up on the idea. But you’d think someone would step up in their place and make something useful.
Last time I link to my project, I promise. I think it really applies in this case. https://getcalculator.app/

It is a pwa, so you can add it to the home screen.

I saw that but I don’t like it because it uses periods instead of commas.
I see, you mean for the thousands separator. It was not localized, you are right.
The default macOS calculator app is also terrible. I can't figure out how to do simple multiplication on it. I'm sure there's an answer but I also don't care to find out. If me typing `5*6` then clicking enter doesn't yield the expected result then the UX is the problem, not me.
The one on windows is terrible and getting worse with each iteration. It's obvious no one with any authority cares and doesn't understand why they should.

Can you drag and drop a number into the calculator? No. I rest my case.

It's open source, just add the feature yourself
iPhone calculator apps are one of those areas I'm "happy to pay for an app but I don't want to pay for a dozen of them to figure out which are garbage and which I like"
This app has a lite version you can try for free.
What a wonderful kludge. People can’t imagine that they would be able to go back and edit, or even see, the history of their calculations, so putting two calculators side by side seems like a brilliant idea.

It’s like if a new word processor consisted of two faithfully recreated typewriters, with a special button to send the most recently typed word back and forth between them.

Indeed, this is, like, a solved problem on every other platform! Apple instead designs their apps after tech from the 80s[1] and is now stuck there for life.

[1]: https://www.creativebloq.com/design/iconic-calculator-inspir...

Indeed, it's a solved problem on iOS too! This story isn't about someone releasing a new app into a desolate marketplace without any calculator apps (and hey, turn that iOS default calculator sideways for some fun), it's a human interest story about someone releasing a new app into an already-crowded market with a slightly new twist, and finding success there.
The issue is that the default Calc doesn’t let you see history and nearly every single 3rd party calc doesn’t follow iOS design principles, just doesn’t look very good, and are often inexplicably slow.
Why does a calculator need to look good?
Why does anything need to look good?
> It’s like if a new word processor consisted of two faithfully recreated typewriters, with a special button to send the most recently typed word back and forth between them.

There's a lot of diff tools that essentially do exactly this.

a calculator with a history being superior was my first thought too. there are advantages to this approach too, however. The history is selective, so if you make a mistake/typo, that isn't now permanently in your history as a footgun to go back to and re-make. here you have two states and you have full control over them.

of course you could also just have a history where you can delete individual items, but this also makes the interface more complicated and might not be as intuitive (and requires more discipline)

Seems like if you allowed swapping out a background set of sub calculators, and provide inter-calculator ops on the front two, you’ve recreated an elegant cross between the RPN and standard calculator models.
> For example, if a user calculates "89 x 15 = 1335" on one calculator and taps the arrow key, the result "1335" will be displayed on the other calculator, allowing the user to continue a problem while the previous equations are still shown on the screen. This makes it easy to notice errors.

While the UI is very different, the key benefit described here reminds me a lot of Soulver: https://soulver.app/

I love Soulver for how quickly it lets you throw together quick guesstimates and sanity checks. The ability to incorporate previous results by reference and update those on the fly greatly improves the clarity and my confidence in my experience.

I like Soulver, and also Tydlig:

http://tydligapp.com/

I love Tydlig!

But have not seen a single update in many years now, and there are a few rough edges in iOS 15 I wish they had fixed. Is it abandoned?

I make heavy use of Soulver. Really quick way to do some quick calculations with good unit conversion.

e.g. I can write hosts = 100; disk_space_used = 10MiB/s * hosts * 3 days as TiB

And it works as expected. Powerful tool when doing capacity planning or other load calculations.

I love Soulver, and I hope Zac is at least considering a version for iPad OS.

I switched my portable setup from a MacBook to an iPad Pro last year and Soulver is one of a handful of small-but-useful Mac-only apps that I really miss when I’m not at my desk.

What’s strange is that they used to have Soulver for iPhone/iPad/Mac and then discontinued this version.
I'll need to give Soulver a shot. I use Calca almost every day, and it seems very similar.

http://calca.io/

I loved Calca, paid and used it for years, but it seems to have stopped development and I switched OS... So I ended up falling back to Excel
A lot of these apps have really cool features, but what I miss most from my Ti-89 titanium days back in high school was the readability of the input and output formulas. The pretty print feature becomes increasingly useful as computation gets more complex. Adding these natural language features for things like built in dimensional analysis would really take it to the next level (as things like units were a slow pain on the ti).

Drawing an integral with limits, fractions, exponents, etc on the screen in normal notation provides much easier error checking when your inputs get longer and contain more and more syntax like commas, parentheses, etc.

Wabbitemu has been my go-to backlit Ti-84 emulator for years on Android. I reach for it before stock calculators every time. :)
Have you tried the Wolfram Alpha iOS app? It's my go-to simply because it lets me enter the whole formula, parentheses and all, instead of having to chop it up. But it also pretty-prints the input after you enter it.
I really want to code a calculator app one day that would take input as RPN, but produce an editable pretty print formula instead of just the resulting stack.
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Every screenshot on the homepage shows an empty window
They're gifs...
Are you suggesting that they're supposed to animate? Because they don't.

Edit: No, they aren't even GIFs. They're MP4s. I have to right-click them and select Play to get them to work, probably because I have autoplay disabled in my browser. So they would have worked if they actually were GIFs, incidentally

Plus one for these sorts of apps! I personally use Numi.
I do think Soulver would be a better choice for many. But it is much more powerful, allowing you to do conversions and labels.

So the simplicity of just having two calculators side by side and a fast way to transfer the results is probably exactly what some people need and want. Zero learning curve, just two calculators doing exactly what you expect.

I'm always fascinated by apps and programs that does exactly one thing, but does it really well (sometimes referred to as the Unix Philosophy). I feel it's harder to find tools and apps like these nowadays. Not sure if there are less or if they are just harder to find because of the huge number of apps overall.

[Edit] Writing this comment actually reminded me of this blog https://onethingwell.org/ which highlights software like this. Gonna try to contact the author and see if they want to add this one :-)

Neat, but a log of transactions would do the same thing, easier wouldn't it? RPN calculators tend to do this nicely.
Yes, but not as fast and intuitive, especially for people of a certain age who are used to working with a desk calculator nearby at all times.
This two-calculator setup has the advantage of being intuitive to anyone despite having only two storage slots. Or rather because it has only two storage slots and they’re always visible in fixed places.
Fair enough. I'll just stick to my history keeping calculators. :)
Some similarities with RPN, except instead of two calculators working on two registers side by side, it's one calculator working on the bottom of several registers.

Both allow you to do complex interim calculations that can be hard to plan out on algebraic alone.

What's interesting is that saving the results of a previous operation to memory and recalling/clearing them (M/MR/MC buttons) has been standard in calculators since the very beginning. It just has the most non-obvious user experience in the world so most people don't even know about the feature.
Being able to visually see the number would be helpful. I haven't seen any that visually show what is stored in memory until you recall it. It would be pretty neat if pocket calculators had a second line for that feature.
Yeah, the current Windows calculator has a tab that shows the memory, and I do use it. It would be nice on a physical calculator.
It can also be confusing and hard to use for a lot of people and once it's failed for a user once or twice, they'll likely give up with it. I have even succumbed to copy n paste as the cognitive load is less and safer.

This however is very obvious and I think it's a great idea. If I had iOS I think I would install it.

It's not just that people don't know about the feature. I'd argue having the side-by-side calculator views is fundamentally different (and much better) than just having a memory-store/memory-recall button. E.g. in this app, you get to see the full equations that went into a particular set of calculations as you go back and forth.
Exactly, the problem with memory buttons is it's easy to forgot (ha!) what's in the memory. With the sibling calculator, you can see everything.
You also can’t perform another calculation with the stored value (other than M+/M-) while also keeping the current accumulator.
I constantly want this feature.

Everywhere.

Making meetings on the outlook app on my phone for work is a complete and utter chore. I can't look at emails at the same time. While I end up popping everything out on my PC on my phone that's not possible.

This is basically the same thing and on a desktop I'd pushed I end up dumping all the info in the scratch pad of an Emacs session phones just don't let you do that.

I believe Samsungs have this feature.

I wish iPhones either supported it in landscape, or got a feature called ‘slide-over’ from iPadOS, where you can float another app on top of your current app, off-screen to the right. There’s a little edge you can then grab and pull over your current app to quickly peek or copy info back-and-forth. When you’re done you just slide back the ‘slide-over’ app.

It’s a really clever feature. And I know swiping on the gesture bar exist, but it doesn’t have nearly the same rapid fluidity of slide-over.

On standard Android phones you can do it. I just tried split screen (GMail on top, Google Calendar at the bottom) and you can create or edit a calendar event while having an open email on top. Looks like this on my phone (Android 13): https://ibb.co/51skSCw
Yes but they mean having an Outlook email open while making a calendar event in Outlook. It's the same app. Since they mentioned Outlook at all it's almost certainly a work email.
That's still possible to do on Android as long as the app allows for that. For example when you compose e new email in Gmail Android app, it starts as a new instance/app and you can split screen, so that you can go through other emails on top half while writing a new email at the bottom half, which is pretty handy when you try to refer to some other email or to fetch some info from another email.
Just use the web version of Outlook and it’s possible.
modal windows should be banned by the geneva convention...
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It's the Norton Commander of calculators
I use M, MR, MC buttons but having 2 calculators is kind of cool too, it is a fun idea.
When I was a little kid in the 80s, there was a SQRT function on my calculator and I would typ in numbers then hit that button and log the results in a scratch pad...

and the thing is that even using the M/MR/MC feature was foreign to me...

The design is horrible and a relic of skewmorphism.

Single tally memory is useful on small screens. I just wish they’d display the stored value somewhere.

The design is:

1. Not skeuomorphic.

2. Indeed, flat.

3. Almost identical to the iPhone native calculator, except it uses round-edge rectangles instead of circles.

From the second image, it appears he set the cornerRadius too high and the buttons became almonds. If that’s what he was going for, then perhaps it IS skeuomorphic? /s
It's skeuomorphic in the sense that the layout is very similar to a physical calculator.
Nope. Skeumorphic design uses ornamentation, like textures and interaction animations, to mimic the aesthetic of a physical object. You don't even need to adopt an existing standard interface layout to be skeumorphic. Make those keys look rubber or give it a mock LCD display and you'd be skeumorphic even if the buttons were in a circle around the display.
It simulates the experience of having two iPhones with the calculator app open next to each-other. iPhones are physical objects.
By that logic, _any_ app is skeuomorphic by default just by existing. IMO that's being too liberal with the definition.
No they’re not. Look into the history of the term it’s from the era where your music playing app would function exactly like a CD player.

For example

iPhone calculator is a skeuo calculator because it has the same layout and limitations of a physical calculator.

Soulver is a non-skeuo calculator because it is built around the benefits of a computer and ignores the history of a calculator.

> iPhone calculator is a skeuo calculator because it has the same layout and limitations of a physical calculator.

In that case you can also consider the iPhone "dialer" to be skeuomorphic, as it has the same layout as the old physical buttons. The digital keyboard is also using the same layout as a physical keyboard.

One could argue that on a touch screen, the buttons are there because it is the most efficient layout and not because it looks like a physical calculator. In that case, it is not skeuomorphic.

The iPhone dialer definitely is. I'm not saying that's bad or anything, some things are better being skeuomorphic if it helps users understand the interface. It's just the actual user interface design discussion gets drowned out by how honestly for lack of a better word embarrassing most digital design discourse is in general it's been changed into more of an art direction debate than a UI design one.

>One could argue that on a touch screen, the buttons are there because it is the most efficient layout and not because it looks like a physical calculator. In that case, it is not skeuomorphic.

It definitely is designed to be a physical calculator though to the extent it is an actual copy of a famous one [1], and has all the limitations of a physical calculator even mincing the memory limitations of a physical calculator.

[1] : https://www.wired.com/images_blogs/gadgetlab/iphone_braun.jp...

Your source image is over a decade out of date. The current calculator has no simulated physical button contour, no simulated plastic face plate, no simulated LCD layout, or any other attempt to be mimic the materials and construction of a physical object. It uses a layout similar to all other calculators because there's no reason to make people change their mental model of entering numbers for computation. Same with the current iPhone dialer. It makes no attempt to appear like a physical object rather than an abstracted method of inputting data. Skeuomorphic doesn't mean "being like something else that exists in some way." The first paragraph from Wikipedia:

A skeuomorph (also spelled skiamorph, /ˈskjuːəˌmɔːrf, ˈskjuːoʊ-/)[1][2] is a derivative object that retains ornamental design cues (attributes) from structures that were necessary in the original.[3] Skeuomorphs are typically used to make something new feel familiar in an effort to speed understanding and acclimation. They employ elements that, while essential to the original object, serve no pragmatic purpose in the new system. Examples include pottery embellished with imitation rivets reminiscent of similar pots made of metal[4] and a software calendar that imitates the appearance of binding on a paper desk calendar.[5]

So a software calendar using the same layout as a paper calendar doesn't mean it's skeuomorphic. It means it's a calendar. If you had a totally unique calendar interface model but added a sewn leather binding graphic along the top, it would be skeuomorphic.

The key to skeuomorphism is that it's based on unnecessary ornamentation, like giving a button on a computer a 3D look, or having a display in an app have a fake glass sheen.
No. No it does not. Does the iphone calculator simulate having an iphone? No. This app juxtaposes two abstracted sets of control buttons. Skeuomorphic doesn't mean "is like something else that exists." The app does not include ornamentation that attempts to mimic the material, motion, structure, or any other physical aspect of the iPhone. If he had a simulated the bezel separating the two calculators or the shine of the glass as if there were two phones physically next to each other, or maybe mimicked the sound made when tapping on the buttons or any other simulated physical feature of the phone itself, then it would be skeuomorphic. That's not the case.
Eh, that's not the problem being solved.

I have the same issue programming when I get popups for various autocomplete or method description or whatever.

Typically, I'm actually focused on the previous line like a hook into my thought process and almost need that hook to get into the next section.

This app is just a simple example of how people visualize the steps into complicated stepping alongside logic.

I press both C and CE multiple times on my calculator to reset it so juggling those 3 M buttons is probably a bridge too far for my brain.
Despite an applied maths degree and a career in informatics, TIL that C is Clear Everything and CE is Clear Entry. Naively, I always assumed the opposite.
Chording them together means “fuck it”
An early form of control-alt-delete.
Alt+hold F4
which will bring you a loop of a "save before quit?" dialog and then killing it :D
Some scientific calculators have a button marked AC for "all clear", also sometimes in a distinctive color so you know it's important. Features like that appear aimed at people like you and me, who aren't specially trained in calculator use and have to reacquire familiarity with what the buttons do when we use the machine upon occasion.
To be fair: if it was aimed at people who don't use desk calculators all day, maybe it should say "clear all". You know, in actual words. Or have a picture of a trash can on it. To me, desk calculators with CA/M/MR/MC... are a design fail.
It’s been a while since I used a calculator, but yeah. I know that the M-buttons do some storage from when I learned about it in high school, but that was a long time ago.
I just learned RPM instead of figuring that out. RPN calc with 3-4 lines of stack display is just more convenient
I was reading about doing log-log calculations on slide rules the other night, and I can tell you that M/MR/MC is even worse than that.
We could also think of it as a spreadsheet with 2 cells.
I know about the feature, I just have no clue how to use it and don't use a calculator enough to bother looking up how to use it.
I know this feature, but I'd much more prefer the workflow of having two calculators side by side.
"If I had asked people what they wanted, they would have said faster horses." -- attributed, apparently wrongly, to Henry Ford.

Those of us who know RPN and other options are likely to squirm at this app, but in this case the "faster horse" approach seems to be easy for people to pick up and understand.

Horses are self driving so if you count the billions invested into self driving cars, I guess we really do want faster horses ;-)
Not aware of any horse from which I can watch a movie on and not have to control at all.
There are plenty of accounts of drunk Victorian men letting their horses lead themselves home.
Depends if the horse knows where it's going. If it's going home, no problem.
Neat feature, IIRC Apple does not have a default calculator app because they can't make one that sets it apart from other apps as is the 'Apple way'. Maybe they should just adopt this one.
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Both iOS and MacOS have default calculator apps. They should look familiar: he copied the interface design exactly for his app.
I first thought it was going to show results in hex and decimal at the same time.
I wrote my own desktop programming calculator that shows signed and unsigned decimal, octal, hexadecimal and binary at the same time. It also allows you to select 8-bit, 16-bit, 32-bit or 64-bit calculations, and do either signed extend (for converting from a lower bit to higher bit legnth) or zero extend. No floating point results though.

It was a fun project to work on.

This seems pretty smart to me.

I think it's being dumped on because it's a "dumb" solution to something that is a non-problem for all of us here, which is probably why I've never seen this solution before. None of us would think of it.

But I think it's true that while most everyone knows how to use the most basic functions of a calculator, most people don't get any further than that, and this allows them to.

I have a degree in Mathematics and I can never remember what C and CE buttons on a calculcator are supposed to do. If you only use them occasionally and in a hurry most calculator apps are frustratingly unfriendly.
Although Soulver like apps are definitely a better solution. I actually think this 2 calculator app is kinda genius in the sense that people over 60 can instantly understand it and fit it into their workflow.
This UI has a better impedance match to the way he, and many people who used desk calculators, think. It's quite elegant.
That's a great way to use that term. I like it very much.
I find it to be very japanese. elegance expressed in such a simple form. blindingly obvious ... now. so hard to arrive at this design choice. i love this. it's poetic.
Wow, I need to look for more contrived but accepted user experiences to fix!
That's a brilliant & simple idea. I love it. Makes me wonder if anyone's made a small screen spreadsheet? Seems like that would be the obvious next step.

Something like a default of 3x4 or 4x4 cells. Would have most of the basic spreadsheet functionality, and maybe simple graphs to show comparisons. Interface designed for touch on a six inch screen.

I've always wanted a browser extension (or similar) that opens a small 10x10 spreadsheet so I can quickly do some calculations. For example, if you are shopping online and have various options that all have different shipping costs etc. It would be nice to do a quick breakdown of costs without having to open Excel.
That would be a great idea! That's the perfect use for the "spreadsheet implemented in Browser" submissions we have seen over the years!
It's a little surprising Google hasn't done this already. A small (maybe inline, maybe floating) popup that gives you a little grid. Would autosave to Sheets. That would be perfect.

Anyways, that's a great idea you have. I never knew I wanted this, but now I want it very badly.

If you paste an expression into the search box… Try it with (66/6)^2/2
It’s pretty fast to pop open a new tab and visit sheets.new, I do this a lot but not everybody knows about it (and the rest of the .new TLD) The in-line floating thing is not too attractive to me. But yeah, new window, sheets.new, split screen, you’re spreadsheeting before you know it.
Same goes for

- docs.new

- slides.new

Super cool!

I think floating would be best. I just had a use case for this today. Was shopping for furnace filters online. They come in a variety of packs (some single, some 4, 12x). They don't always list the per unit cost, so it would be nice to quickly open a floating 10x10 table, list out a few options and get a per unit breakdown to find the best deal.
I'd like to use this for daily driver.
Numbers runs on iOS—not terribly easy to use, per se, but absolutely gets the job done. There was a light version of Excel even on the BlackBerry-styled Windows Mobile phones that similarly was great for, oh, comparison pricing or converting multiple values other tiny math jobs.

One specifically designed for phones with a very limited feature set, though? That could be very handy.

I occasionally fire up Numbers on my i-devices. It's ok on iPads. But on my iPhone it's a bit painful. Haven't tried it on there in a few years. I should try it again to see if works better on the small screen now.
I can highly recommend https://bbodi.github.io/notecalc3/notecalc

Web based Soulver-like calculator that is a bit more like scripting.

totally different, but wonderful.

This is great, but I can't seem to copy the result. Is it just me?
oh weird, not just you. In the export preview you can, hope there is a better way though.
found it out:

hit ctrl+c in any line (without any character selection) to copy the result.

Thank you, but I wish we could manually select it and copy the desired part (for example when converting days to seconds I'm only concern about the actual seconds, not the "seconds" suffix)
The best feature on the Mac's built in calculator is the paper tape (⌘+t) which I stumbled on ages ago while accidentally having the calculator open and trying to open a new tab in my browser.

I always leave it open now and it has saved me countless times. Really with the iOS version had this feature built in as well.

Woah, thanks! This is an awesome feature I never would have found on my own
Thanks for the tip! Interestingly, I found it weird how the app handles order-of-operations.

That is, if you type 1 + 2 / 2, the answer shows up as 2 and the paper tape shows

  1 + 2 / 2
  = 2
However, if you type 1 + 2 = / 2 (that is, you type equals after the 1 + 2, which will show 3 on the screen, before typing the / 2 part), the last line of the paper type shows

  1 + 2 / 2
  = 1.5
They need to add some parentheses in there.
It's the accepted order of operation in maths that you resolve multiplication and division before addition and subtraction.

While the single-value-view of a calculator removes visual context, if you are banging out multi-step calculations as a power user not having the standard order of operations would be odd.

The workaround, as you say, is to just press enter (equals) after each required subtotal. This is pretty semantically clear, that is - if you consider a traditional keyboard to even be a thing that young people are familiar with - and that is getting arguable!

Key corollary issues to the single-value-view nature of computer calculators are that they pull a lot of (now obtuse) cultural context from physical calculators plus regular mathematical context, none of which is obvious to occasional computer calculator software users.

It's probably high time this stuff was rejigged. Thanks for the paper tape tip!

Their stated issue is that pressing enter after the 'subtotal' is not clear because it shows as `1 + 2 / 2` in the history instead of `(1 + 2) / 2`.
To be clear, I'm not arguing that the results from the calculator are wrong, and I totally agree that how it handles order-of-operations is correct.

What I am arguing is that the visual display in the "Paper Tape" view is wrong because it displays different answers for the same values.

Android's calculator also has the history, invoked by pulling down on the display part. (Perhaps obvious to everybody here, but after the discussion on how the memory function is unclear to people, I'm not so sure.) Also that history is saved between launches, which happens to be extra useful for me.
Oh, that is useful.

Now if only I could calculate the log of something by pressing 'log' that would be nice.

I think that my Android phone (a Chinese model with Android 11 Go) has the Android calculator, which IIRC was based on the old SGI Irix calculator.

If to the right of the 4 basic operators +, -, ×, ÷ you have a vertical strip (greenish in my case), you can slide it to the left and have access to various other operators/functions, including log.

Being based on the old SGI calculator, you can also slide any result to the left to get as many digits after the decimal point as you like.

e.g. slide in the extra ops, press π, then start sliding the 3.1415… result.

I think the guy was saying that you have to surround an expression with ‘log()’ to get the logarithm—which is inconvenient when it's a result of previous calculations and you have to shuffle the cursor around. Can't just slap ‘log’ and have the current expressions logarithmized.

However, seeing as the calculator allows writing expressions with multiple operations, just shoving everything on the screen into ‘log()’ would be unreasonable, as one might want to provide the exact place for the logarithm themselves—so I guess the app does the most reasonable thing it can.

No, I've been using the Android calculator for years and never realized that it could do that. This is the problem with "clever" UX...
I never clued in to the fact that the little bar below the calculator screen meant that you could pull it down to show history either.
Coincidentally, history is also available via the three-dots menu =)
Speaking of cryptic UX, though that one at least is standardized nonsense.
History is nice. I do wish it had the memory buttons.
You can just select and copy, and then paste. The whole expression is editable as a line of text.
Thanks to this post, I played with the history and discovered that if you tap an expression in your history, it becomes the current expression.
Qalculate as such a feature and is my preferred calculator app :)
Not sure if this app can do stuff like cross multiplication or run the same operations on both calculators.

But this app reminded of something similar.

There is an old school double mechanical pinwheel calculator:

https://www.youtube.com/watch?v=qnlzKCFP0sU

It was probably mostly used for coordinate calculations.

I own one of those brunsvigas (the single stage one) and it is fascinating what these things can do.

A mechanical calculator with enough didits can solve cross multiplication rather easily.

Some of the strong points of this calculator is the main thing I use in RPN calculators with stacks. It's so helpful for me to duplicate a value and then operate on that, and be able to throw it away if I mess up, sanity check from where I started at intermediate calculations, etc. it's not identical, but many points others are mentioning in this thread are what I value from an RPN stack based calculator.

BTW, for anyone who is comfortable with RPNs, MacOS added the mode to their built-in calculator recently-ish. it's not terrible either. I've switched to it for my default experience. (even though nothing beats the HP 48g, as it's what I'm the most familiar with).

Also, on the article, really cool that someone added this on mobile. I love hearing about devs developing something that fills a niche and does so well. I feel like I'm out of ideas most days. Good for her!

I was thinking the same thing while reading the article. I have been using RPN calculators for 40 years, and it has become second nature to manipulate the stack to have two calculations going at the same time, and then merging them, if needed.
What's the RPN based calculator you use on your terminal? I'd love to learn!
dc, perhaps.
Not sure what the parent uses, but emacs has calc, which is a RPN calculator with lots of features (including history and intermediate results) and can be used in the terminal
To be honest, I mostly use a physical calculator (Swissmicros DM41L, which is an HP41CX clone). Second choice is the i41CX+ app on my phone. The HP41 keyboard and operational patterns were etched into my brain at university, since my first engineering calculator was an HP41C.

I have used rpncalc and T_REX (https://isene.org/2021/02/T-REX.html) in the terminal, dc or gforth in a pinch.

On that note, I always end up using an HP 48g emulator on my phone as my main calculator app. I've been using Droid48 for many years now [0]. I'd initially looked at most of the native mobile calculator apps before realizing that since I was comparing them all with the HP 48 experience, I might as well just use an emulated HP 48 and be done with it.

On a laptop or desktop, though, I've come to use Emacs Calc [1] pretty heavily. There's a surprising amount of power in it. It's pretty cool to be able to do things like operate on matrices of symbolic expressions via a stack interface.

[0] https://play.google.com/store/apps/details?id=org.ab.x48

[1] https://www.gnu.org/software/emacs/manual/html_mono/calc.htm...

I find Hiper to be almost perfect for its clearer UI than a rendering of a real device and, especially, for its prominent binary and hex radix modes.

But it lacks the stack undo of the 48 emulators.

I came here to write this.. Yeah, I'd have thought that dual-calculator thing was brilliant if I hadn't turned to RPN.
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For the HP48/50 fans here: try the HP Prime. The color display is amazing. It requires some relearning because the UI is different, but it still has full-featured RPN mode. The keys are good, too--it looks and feels like a proper HP calculator. I used a 48SX in college and 50G later, but the Prime is the one to have now. (It's also the one my daughter steals now that she's in more advanced math and science classes.)
Improving upon the design of a calculator app is incredibly difficult. And before people complain that it's not improved, yes it is. For most people, this is way better. Congrats to him, he's living the dream. Building software that does a job, and then getting paid for that software. I just hope he doesn't suffer too many copycat apps.
This article made me realise why I use a python shell over a calculator app. It's nice to refer back to my previous computations and results. Several people here mention RPN; I work in tech, definitely understand stacks and get that I would be able to view my previous computations. Yet it's not something I took the time to discover, there were always other ways.

I've always believed that there is still a lot of low-hanging fruit left in crafting user friendly experiences for consumer facing applications. Who would have guessed this would be the case even in the design space of something as fundamental as calculators! ~20k paid users seems surprisingly large. But I'm not plugged into the app dev scene, so perhaps this isn't unusual.

> I just hope he doesn't suffer too many copycat apps.

There were 2k clones of flappy bird within a month of its release. By now there must be at least a dozen programmers copying this idea (Twin-Calc) for other platforms, myself included.

My daughter is struggling with this problem: on TI-84s, "(-) 3 x^2 Enter" gives -9. Personally, I think that if you have a dedicated negation operator it should have a higher precedence than power, but at the very least the calculator could highlight what it's doing.

"Hypercalc" the Android app does it, but TI-84 is the standard..

Obligatory but futile plug for HP RPN calculators.
Seconded. But I'm afraid RPN is an endangered species. Who's learning it anymore?
Probably every computer science student learns it in order to implement something useful after learning about the stack.
> a dedicated negation operator it should have a higher precedence than power

I prefer the traditional precedence; it ensures - 3 ^ 2 = 0 - 3 ^ 2

I understand the argument, I just wish that the most standard school calculator would highlight somehow what it's doing

Another one is "2 ^ 1 / 2 Enter". Some calculators give 1, newer ones give sqrt(2).

I'm not sure what the parenthesis around the negative sign is supposed to accomplish. Generally you put it around two or more operators.