Instacalc is a different kind of calculator. First of all it is online, but interactive – it allows you to view answer as you type. It is a slim down version of spreadsheet, which it has number of useful function calls and graph drawing functionality. Another interesting feature is sharing, which you can insert a javascript snippet into your web page.
Cool eh? This is pretty useful for doing some quick calculations, but normal calculator couldn’t do justice because it is too simple, or spreadsheet is an overkill for it.
