FlashUnits is a units conversion program that can convert over 800 units in several categories. It has a clean and easy-to-use interface that is thought to allow the user to find the required units or conversion fast. It's highly configurable and intuitive and best of all, it's free.

FlashUnits supports, between others, the following conversions:
1. Acceleration
2. Angle
3. Area
4. Capacity and Volume
5. Distance and Length
6. Mass and Weight
7. Speed
8. Temperature
9. And many other

The license of this software is Freeware, you can free download and free use this unit converter software.