Omni Calculator - Helping you make rational decisions, one calculation at a time.
Soulver - Soulver is a software application that functions as a calculator that allows you type a continuous stream of information rather than having to input data into multiple cells.
Numbr - An elegant calculator for the web
Calca - Calca is an advanced symbolic calculator for iOS, OS X, and Windows that's as easy to use as a text editor.
Numi App - Numi is a beautiful text calculator for Mac.
Pry Financials - Finance for Founders