Instacalc – Online Calculator
Instacalc is a web application that gives you a fully functional calculator right in your browser. It supports unit and currency conversions, and it can do trig and log functions.
You can embed live calculations in a website. For example, I have embedded some simple calculations below, and you can modify them as you wish. The results appear as you type.
While not as powerful as Tusanga Calculator (which we discussed here), Instacalc is a very useful tool for most calculations.
Visit Instacalc for more info.