http://www.calculator.org/ has a free version of Calc 98, a little Windows-style calculator that has about every conversion I can think of. They also have an on-line version, but it is new and doesnt have the full features. Key in a value, click UNITS, then select the FROM and TO units. It even converts from pennyweights to scruples and other useful units. How nice. I believe it is from Great Britian, so some terms are a bit obscure.