Soulver 3 for Mac - A smart notepad with a built in calculator
PercentageTools.com - Percentage calculator, online calculates percentage in many situations, simply enter the numbers and get the result and the formula of calculation.
Omni Calculator - Helping you make rational decisions, one calculation at a time.
Percentage Calculator - The percentage calculator to make your life easier
Numi App - Numi is a beautiful text calculator for Mac.
Bond - A simple app that reminds you to keep in touch with people