Hi, I just uploaded a handy library for managing engineering units. It provides a Num type that allows you to mix units into calculations. It also converts between units automatically and will error out if you try to mix values with inconsistent units. Here's an example that computes the horsepower of a hydraulic pump (power = pressure * flow): flow = 20 * gpm -- Gallons per minute. pressure = 3000 * psi -- Pounds per square inch. power = pressure * flow powerHP = value power hp -- Get the value in horsepower. powerKW = value power kw -- Get the value in Kilowatts. If you don't see your units in the library, it's easy to add new ones: mm :: Value mm = 0.001 * m Wish I had this back in college. -Tom http://hackage.haskell.org/package/engineering-units