Units and conversion factors

Powers of 10

Prefix Symbol Value Prefix Symbol Value
atto a 10−18 kilo k 103
femto f 10−15 mega M 106
Pico p 10−12 giga G 109
Nano n 10−9 tera T 1012
Micro µ 10−6 peta P 1015
Milli m 10−3 exa E 1018


G, T, P, E are called milliard, billion, billiard, trillion in Europe, but billion, trillion, quadrillion, quintillion in the United States. M is universally used for million.

SI Units

Basic Unit Name Symbol
Length Meter m
Mass Kilogram kg
Time Second s
Electric current Ampere A
Temperature Kelvin K
Luminous intensity Candela cd
Plane angle Radian rad
Solid angle Steradian sr

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