MetricMaster is a measurement conversion calculator for the Macintosh, containing over 2,000 metric/S.I., imperial, U.S., and other units in its database, most to 14 significant digit precision. New units can be added and unwanted ones removed. Supports ft/in/fractions, different number formats including scientific notation, and complete control of significant digits. Can also convert currencies, clock times, and many physical constants. On-line info is available on the history and development of modern measurement systems. Also contains 600 unit definitions.