Soulver is a smart notepad with a built-in calculator. It gives instant answers to any calculations it finds in your text. It's a better way to work stuff out than with a traditional calculator, and a more lightweight tool for quick calculations than a spreadsheet.
OpalCalc is a brand new type of calculator for the PC. As easy to use as Notepad or a word processor, OpalCalc allows natural language in the sum and multi-line support so you can go back and adjust your previous calculations on the fly.
µCalc (mucalc) is a multi-user math web app. The math syntax is parsed in the browser by math.js.Discontinued
Project stopped. The source code is archived here: https://github.com/antoineMoPa/mucalc.com
Calculist is an open source application that facilitates effective thinking. Write down your thoughts, ideas, and data in the form of lists. Focus your attention by zooming in to a specific list, and zoom out to see the broader context.
A web based calculator with a clean interface that allows commenting, creating variables and more. The website also provides more tools like converter, VAT calculator, and more.