Offers a wide variety of unit conversion tools and conversion charts for fast lookup.
British Weights and Measures Association (BWMA)
Pressure group opposing compulsory metrication. Political, consumer and transport information, discussion boards and links.
Conversion Factors for Energy Equivalents
Physics laboratory of the National Institute of Standards and Technology (NIST) sponsors and maintains this reference resource of CODATA-recommended values of fundamental physical restraints.
English Weights and Measures
History and usage of English/Imperial/customary weights and measures, with conversion factors, and pictures. Minims, drachms, pecks, bushels, rods, poles, perches, furlongs, ounces, fathoms, pints, gallons, nails, chains, chaldrons, tods, crowns, florins, groats, farthings and guineas.
A dictionary of units of measurement: explanations of the metric system, System Internationale (SI), English customary system, and other modern measuring systems. Plus extensive links to other measurement-related Internet resources.
International System of Units
Definitions of SI units and SI prefixes, units outside the SI, rules and style conventions, historical context for SI units, international aspects of the SI, and unit conversions.
Metric 4 US
A site promoting the metric system which argues why metric is better and English is worse. Provides an English-metric online calculator.
Metric Conversion Tables to Imperial Measurements
Standard-to-metric conversion factor tables with definitions, derived units and prefixes.
SI Units, Conversion and Measurement Skills
Book by Wacek Kijewski on experimental science in metric units. Includes problems, guided solutions, fun facts, data handling and metric conversion tests.
The Foot Rule
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.
Units of Measurement
Conversions tables and equivalences of the principal units of measure of the SI and Anglo-Saxon systems.