Soulver: Reinventing the Calculator on OS X

Our sister site, iPhone.AppStorm, reviewed the iPhone version of Soulver back in March this year. When I read that piece, I was really taken with the app, though I didn’t think that I needed a calculator much in my day-to-day life. I also read the excellent piece by Marco Arment that’s linked in a note to the review, and that got me fascinated by the application’s user interface, and the subtly disruptive things it does with familiar expectations for how a calculator looks and works. So I took myself over to the App Store and paid my money.

And then I realised that, actually, I use a calculator just about every day at work – a grey little handheld number that’s always disappearing onto my colleague Mary’s desk. I lose track of the number of times I’ve had to re-enter a column of numbers to check I’d got them right, and the number of times my sum turned out different on each of two or three checks.

So I started using my iPhone and Soulver for doing these calculations, and found the ability to check and refer back to previous lines invaluable.

I knew that Soulver began life as a desktop app (actually, quite a long time ago: you can read more about the history of the app in this 2006 press release), so I had to download that and see if it was as good as the iPhone app. I got in touch with the developer, and learned that they were soon to release a new version, Soulver 2. Well, that happy day has come, and here’s a quick walkthrough…

The Basics

Andrew’s review on iPhone.AppStorm outlined how the iPhone app works, and that tells you most of what you need to know about the desktop version. The layout and the basic UI experience is very similar:

Soulver Interface

Soulver Interface

You have your entry panel on the left, which has a white background, and that pale-blue right panel is where your answers will show up as you type.

The menu’s six icons, of course, show where the desktop version is different. From left to right, these buttons let you show or hide the line numbers on the left of the entry panel, show or hide the Format Bar (immediately under the menubar), open the Numbers settings window (more on that in a moment), display your current answer very large, insert the answer from the previous line into the current one, and show or hide the Answer Palette.

Big Answer

Since the first one of these needs little explanation, and Format Bar and Number need a bit more, let’s leap over them and start with Big Answer, which does exactly what you’d expect: display the current line’s answer in numbers that fill your screen:

Large Numbers

Large Numbers

This can be handy in a number of situations – if you’re needing to write down the solution to a problem, if you’re working alongside someone, or a group of people, who need to be able to read your screen from a distance, if you’re using the app to demonstrate a mathematical problem, etc.

Format Bar

The Format Bar lets you set various parameters for the current line: your number base (choose between Decimal, Binary, and Hex), the number of decimal places, whether or not a thousands separator is displayed, the notation style (which either shows large numbers as, say 1,000,000 or 1M), and the basic trigonometric mode – either Degrees or Radians.


Clicking the Numbers button brings up a very useful window:

Currencies & Variables

Currencies & Variables

From here, you can set the value of variables – click on the Variables tab on the left, and then on the + in the bottom row, and you can define any string as a particular value: so x can equal 100, or y, 912. Once these are defined, you can simply enter y*12, and Soulver will deliver your solution of 10.944k (or 10,944, depending on which Notation setting you’re using).

In the Stocks tab, you can enter the details of any particular stocks you might be tracking, and Soulver will periodically update their value. That’s great if you’re using the app to keep track of any kind of personal finance maths!

Stock Calculations

Stock Calculations

And, finally, in the Currency tab you can set your base currency and see the codes you need to use to reference any of the currencies Soulver automatically updates. So, for instance, if you want to work out what a licence for Soulver costs in UK money, you would simply type: $24.95 in £, or 24.95usd in gbp, and your answer would display immediately in the right hand panel:

Variables In Use

Variables In Use

In that screenshot, you can see that some text is highlighted in purple: these are phrases that Soulver has recognised as variables – either those that I have defined, as above, or inbuilt variables such as predefined currencies.

Add Answer Token and Answer Palette

The final two menubar buttons are Add Answer Token and Answer Palette. The first of these allows you to insert on the current line the answer of the line immediately preceding – very helpful if you’re working on a list of related sums. And the Answer Palette (which is also available by clicking on an ‘i’ symbol that appears when you mouseover a line) displays some immediately useful information about the selected line – in this case, conversions to several other currencies:



In other situations, the information displayed will be different: conversions of the result into Hexadecimal, Binary, and Degrees, and a Fraction value in cases involving decimals.

In Use

As I said above, I’m no math expert, and my needs are quite simple. I’m likely never to need to make use of most of what this clever app can do. But for the simple, occasional mathematical problems I need to solve, I would go to the extent of taking my MacBook into work (where we run PCs) just to have access to this app whenever I need to crunch numbers.

There’s a great screenshot on the developer’s site, which shows some of the extended uses of Soulver:

Extended Uses

Extended Uses

You’ve got to love that ability to mix words and text so that you can more easily find your way back through calculations: this alone makes the app much more useful than an ordinary calculator.

Where you might otherwise sit with a sheet of paper, needing to write down the solutions to a list of sums as you go, it’s so much better to be able to annotate your workings. And when you’re done, Soulver can easily save your workings, export them in a few different formats, or print them so you can take them off to that dreaded finance meeting.

That last point, about mixing numbers and words, calls to mind the other way that you might go about making such calculations – using a spreadsheet. Really, that’s the genius of Soulver: it does the things that spreadsheets do, while maintaining the ease of use of an adding machine.

But it reinvents the calculator, and in that process, I believe Acqualia have come up with a real piece of genius.


Soulver helps you work things out. It's quicker to use than a spreadsheet, and smarter and clearer than a traditional calculator. Use Soulver to play around with numbers, do "back of the envelope" quick calculations, and solve day-to-day problems.