SI unit

Standard metric measurement

An SI unit is any of the standard units of measurement in the International System of Units (Système International), the modern metric system used globally in science and most countries.

The seven base SI units include the meter (length), kilogram (mass), second (time), ampere (electric current), kelvin (temperature), mole (amount of substance), and candela (luminous intensity).

Derived units like the newton and joule are built from these.

base

kilogram

Base unit of mass

meterDevice that measures usage
ampereUnit of electrical flow
moleSubterranean insectivore

candela · mass · length · time · current · temperature · amount · luminosity

derived

joule

SI energy quantity

wattUnit measuring power
newtonSI force unit
pascalSI pressure unit

volt · ohm · hertz · tesla · farad · henry · coulomb · lumen · lux · gray

prefixes

kilo

Thousand-unit prefix

megaMillion-fold prefix
gigaMetric billion multiplier
milliOne-thousandth prefix

micro · nano · pico · centi · hecto · peta

metrology

calibration

Adjusting for measurement accuracy

standardizationImplementing uniform technical specifications
measurementDetermining size or amount
accuracyDegree of correctness

precision · tolerance · resolution · traceability · uncertainty · reproducibility · prototype · definition · reference

conversion

metric

Standard of measurement

imperialRelating to supreme rule
conversionAct of changing states
equivalenceState of being equal

interoperability · compatibility · harmonization · international · universal · adoption

Opposites

measurement system

SI unitimperial unit

Nonmetric standard of measurement

traditional unit · furlong · stone · bushel · fathom

Family

second, SI units

Familiarity: Top 500,000
Profile: Used worldwide · Timeless · Rated G