Soulver helps you do quick calculations and work things out. It's quicker to use than a spreadsheet, and smarter and clearer than a traditional calculator. Use Soulver to do "back of the envelope" quick calculations, and solve day-to-day problems.

Numi is a handy calculator app for macOS. It allows to describe tasks the natural way and instantly get an accurate answer. For example, $20 in euro - 5% discount or today + 2 weeks