3 Numbers: A traveler’s multitool from the future of the past.

Drag and drop numbers between calculators with a gesture and keep numbers between sessions
Convert currency (please read the list of available currencies on the support page)
Convert measurement units
Calculate tips
Check a highly-condensed tipping guide
Use a calculator
Track expenses (or anything else) with the notes utility
Export your expense notes as an rtf file or a csv for import right into Excel or another spreadsheet program (they’ll be available on any desktop computer with a web browser via 3 Numbers’ built-in lightweight web server – no need to sync first!), or email them to yourself or someone else
3 Numbers has a striking steampunk interface and an alternative look which is entirely modern – it’s your choice
Only $1.99, click or tap here to buy.

Screenshots of 3 Numbers:

View the 3 Numbers movie to see complete usage: