Joshua Johnson has written a great post on building your own design calculators with InstaCalc. I love what he had to say:
Instacalc is that perfect product that sits somewhere in between a normal calculator and a spreadsheet. It’s much more powerful than a calculator and not quite as complex as a spreadsheet.
Here's an example of how he put it to use:
Quick reminder: You can add any calc to your site in seconds. Just add the embed code:
<iframe src="http://instacalc.com/8547/embed" frameborder="0" marginwidth="0" marginheight="0" width="450" height="410"></iframe>
The idea is to quickly whip up your own design grid, and see how the parts fit together in front of you. Awesome example Joshua!
The InstaCalc Mac App has been released (details here). It's been a long-time coming, and I'm considering an iOS version in the near future.
I must say, it's pretty handy having a calculator a keyboard shortcut away :). I've gotten some great feedback so far, and the app will continue to be updated. Get it here.
InstaCalc is great for quick product pricing estimates. Check out this example for pricing piano accompaniments:
Type in a number and get an instant estimate. No programming required!
Jay Shep has a great post about how to calculate your real hourly rate:
Seem low? Well, are you accounting for all the time you spent learning that skill? You don't just pay an artist for the time it takes to make a painting: you're paying for the years of experience that got him there.