Calculator is an extension for Mozilla and Firefox. It has an interface similar to Microsoft Powertoy Calculator. And it's a great open source replacement to the calculator included in Windows accessories

Features:

• History of calculations
• Many conversion functions
• Print calculations
• Easy to use interface
• Many functions

Lastest changes

https://addons.mozilla.org/en-US/firefox/addons/versions/1194

FAQ:

• What is wrong with %, it's not working?

The % is not percentage but the modulo operator. For more info on this operator, modulo.

• How can I create a shortcut on my desktop (XP) or in start menu to launch Calculator directly?
1. Create a text document on your desktop
2. Rename it "calculator.bat"
3. Right click it and select "edit"
4. Copy the line below in the file and save the thing: "c:\Program Files\Mozilla Firefox\firefox.exe" -chrome "chrome://calculator/content/calculator.xul"
5. You can now open the calculator by double clicking "calculator.bat"