Soulver 3 review: Mac app simplifies readable calculations and conversions

Calculations are for computers, but Soulver makes them human again. The app, overhauled for version 3, lets you type in readable and formatted arithmetic calculations, functions, dates, and unit conversions, and get results you can use.

It’s particularly useful if you’re constantly working among combinations of units, such as throughput over time (Mbps per hour), or frequently return to the same calculations into which you plug different values.

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Soulver is not a calculator as such, even though it can handle any math you type at it, no matter how long the set of operations. (If you want a calculator, try PCalc.) Rather, it’s a way to work comfortably in a math and units environment for reckoning problems often needed in day-to-day life.

You can use variables to create different scenarios with the same number, track sales and commissions, or figure complicated volumetric totals without having to build a spreadsheet. Text-formatting options and commenting let you keep it all readable and self-documented, too.

For instance, instead of figuring out the calculator approach to a percentage, often requiring a specific sequence of hitting the % button, you can type into Soulver, 20% of $12.11 and be instantly presented with $2.42.

And I don’t know about you, but when I’m using a recipe with imperial measurements, making sure I get teaspoons, tablespoons, and cups correct when I’m doubling or halving? I’d rather type 8 tablespoons in cups into Soulver and find out the answer (half a cup). If you need custom units, you can add those, too.

Soulver divides itself vertically: calculations and statements appear at the left and results at the right. You can type in a large variety of math and conversions, which include straightforward calculations with parentheses and order of precedence, as you may remember from math classes: (2.5 + 7.5) * 1.11 / 10 - 15^2. (That’s -223.89, by the way.)

The revised version also offers more ways to get results by entering something that resembles plain speech while still conforming to a structure, so you can hunt for an answer through relationships of existing numbers.

A unique hover-over slider feature allows “scrubbing” through numbers to see outcomes, allowing you to run through a lot of alternatives quickly without typing. While that’s not recommended for political decision making, it can be useful when you’re tweaking sizes for a wall hanging or how many miles a day to drive for a trip.

New in version 3 are two features that require adhering more closely to syntax than most of others in the app. A “rule of three” feature in which Soulver can fill in the blank. This is great for proportions. You state one of these in the form “number is to number as number is to what,” as in 9 is to 16 as 27 is to what (answer: 48).

With dates, you can’t enter arbitrary calculations, as Soulver relies on an Apple math library for dates. But you can find a lot of results that would otherwise involve manually counting off days or weeks on a calculator. June 1, 2019 - 6 weeks, for instances, gives you April 20.

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A common issue for those of us who transfer large files over networks and the internet is getting a decent estimate of the span of time that copying those items will take or what the capacity of my throughput is. I turn to Soulver regularly for this, as it accepts calculations like:

• (120 Mb/second) × 100 hours in TB (5.4TB)
• 1 TB / (120 Mb/second) in hours (18.5 hours)

Capitalization remains important in units here as in others: a megabyte (a million bytes) is capital M and B (MB), while megabit (a million bits) is capital M and lowercase b (Mb). While this long-running similarity can be a problem in other realms, it’s easy to be off by a factor of eight here.

Soulver shows a lot of numbers after the decimal point for results that don’t divide or multiply neatly, which is called precision. The default is 10 digits, which is useful for certain kinds of mathematical results and scientific calculation, but far too much for everyday use. You can hover over a result, click the Round icon (≈), which lets you adjust to the degree of precision you need.

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The latest version lets you collect Soulver files into a kind of notebook, so you can move among them through a sidebar and organize them as well. It also makes it easier to find projects you’ve worked on.

The revision isn’t without bumps for previous users, such as this reviewer, as Soulver’s developer replaced the underlying third-party math engine with a superior one that’s still a work in progress for some outlying features, like data units. However, through micro-releases in version 3.0 and a major 3.1 release, my concerns were answered.

A few features remain absent. The precision adjustment above could be set as a default for all new calculations in Soulver 2 and then be overriden where desired; the developer said it’s slated in a future release of version 3. Line numbering is missing as well, but slated for future addition.

Bottom line

For freeform calculation entry, especially converting units and calculating currencies, Soulver provides answers with little effort and great flexibility.