The International System of Units (SI)
A unit of measurement is a particular quantity, defined and adopted by convention, with which other quantities of the same kind are compared in order to express their magnitudes relative to that quantity, for example the kilogram, metre, litre, volt and second. Almost all countries in the world have regulations on the use of units. Starting point mostly is the International System of Units, indicated as SI.
The SI basic units
The 7 basic units: metre, kilogram, second, ampère, kelvin, mole and candela.
Some important derived units
These are derived in a coherent way from the 7 basic units.
Some important derived units with own name and symbol
Definitions of units like hertz, nemton, joule, coulomb, watt and gray.
Prefixes
Tera, deca, micro, femto … prefixes from 1024 down to 10-24.
Full overview
For a full overview you can donwload the SI-brochure form the BIPM website.
