If you have a variety of postage stamp denominations, and you've ever had to come up with an arbitrary postage, like $1.87 for example, then StampCalculator is for you!
Use StampCalculator to keep track of your stamps, and compute postage with minimum overage for any amount, based on the stamps you actually have!
StampCalculator is in beta, and currently has only one mode: Find the minimum overage for your postage without going over a limit of 10 stamps. If no solution is found with 10 stamps or less, then StampCalculator will "waive" the 10-stamp limit. Future versions will have more choices, such as setting any limit, or no limit, on the number of stamps, or minimizing the number of stamps within an overage limit.
I'd love to hear from you! Please email me your ideas and bug reports.