Months ago, I heard Marco Arment [mention](http://www.marco.org/2010/01/04/soulver-for-iphone-the-iphone-port-of-my-favorite) an application for his Mac called [Soulver](http://www.acqualia.com/soulver/) ([Acquailia](http://www.acqualia.com/) $25). It sounded great, but when I went to the website, the price chased me away. Why would I need to spend that kind of money on a non-standard calculator? It seemed crazy to me, especially since I don't work with numbers that often.
Then I found myself producing a list of applications that I wanted to install on my new Macbook Air. For each item, I had the title and a price next to it -- all plain text as usual. Once I was finished I had 50 or so items in the list and was thinking to myself "OK, now what's the quickest way to total these up?". There are dozens of ways I could have done it but my mind drifted back to Marco's post and a light went on.
What the hell. I'll try it.
I downloaded and installed Soulver and cut-and-pasted the list of apps into Soulver and -- bingo -- the list was sub-totaled and totaled in a second. Now I could even play around with the lines, moving them around to make more sense and give me a better idea of where my money is going. All of my text labels were there but dutifully ignored by Soulver. It functioned exactly the way you would expect it to, intuitively. The syntax highlighting was helpful as well.
That was neat but it was unclear such a need would ever surface again. But it has surfaced, time and time again. If I'm doing some brainstorming on costs for my team resources, or time budgeting, or travel costs, it's a cinch to open Soulver and start plugging in numbers as variables:
milesToWork = 35
milesPerGallon = 22
costPerGallon = $3.16
totalCostPerWeek = (((milesToWork * 2) / milesPerGallon ) * costPerGallon) × 5
totalCostPerYear = totalCostPerWeek * 50
Wow. I spend approximately $2513.64 per year to drive to work every year, not including tolls. But what if fuel goes to $3.61 per gallon? Just change the costPerGallon variable and I know it will now cost $2871.59. Ouch.
I do this kind of forecasting a lot more than I thought I would and Soulver has become an valuable part of my workflow for dealing with numbers. Sure, I can still bang out a quick calculation with Launchbar when I need to, but for more interesting number work, Soulver really is hard to beat.