A restaurant tip calculator for your iPhone
Most of the options are pretty self-explanatory. You've used a tip calculator before, right? I know, there's a thousand of them already for the iPhone.
Make CHECKSUM is kinda cool. It comes from something I read on BoingBoing. You can use it to catch mistakes in your bill or tip fraud (when your waiter or waitress alters your tip after you've signed the receipt). TippyTops will adjust your tip up (no sense in stiffing our servers because we're paranoid!) until the grand total creates a checksum. Add up all the digits to the left of the decimal point and divide by ten. The remainder is equal to the right-most digit. So, if your grand total is $129.42, your bill checks out. If the amount is miskeyed as $139.42, you can quickly see on your bank statement that 1 + 3 + 9 does not equal 2. Don't forget to save your copy of the receipt, or at least take a picture of it.
Click on "Save Settings" to save your current tip percentage and tip option selections to a cookie on your iPhone. Next time you visit, they'll be automatically selected.