Quad-Lock Unit Converter is freeware from a company the deals with insulated concrete. Sounds like an odd provider, but the application is light weight and works well. It will convert almost any unit of measure to another comparable unit in just a few clicks.

The links here take to you the application page, bypassing their home page, which is just a click away should you be interested in their product.

http://www.quadlock.com/about/unit_converter.htm