• IntroductionSystem of measurement
  • HistoryCurrent practice
  • Metric system
  • Imperial and US customary units
  • Natural units
  • Non-standard unitsAreaEnergy
  • Units of currency
  • Historical systems of measurementAfricaAsiaEuropeNorth AmericaSouth America
  • Ancient
  • See also
  • Notes and references
  • Bibliography
  • External links