Offers a wide variety of unit conversion tools and conversion charts for fast lookup.

Convert units from one measure to another (e.g. meters to yards, liters to gallons). A very extensive collection of units and categories. Includes usage and definitions descriptions of units and categories.

A site promoting the metric system which argues why metric is better and English is worse. Provides an English-metric online calculator.

Standard-to-metric conversion factor tables with definitions, derived units and prefixes.

Book by Wacek Kijewski on experimental science in metric units. Includes problems, guided solutions, fun facts, data handling and metric conversion tests.

Pressure group campaigning for the completion of metrication in the UK. History, legislation, and practical help.