Metric system

Base units*

physical quantity unit symbol

length metre m

area square metre

are (100 square metres) square m, or m²

a

volume cubic metre

stere (1 cubic metre) cubic m, or m³

s

weight gram

metric ton (1,000,000 grams) g

t

capacity litre l

temperature degree Celsius °C

Prefixes designating multiples and submultiples*

prefix symbol factor by which base unit is multiplied example

exa- E 10¹⁸ = 1,000,000,000,000,000,000

peta- P 10¹⁵ = 1,000,000,000,000,000

tera- T 10¹² = 1,000,000,000,000

giga- G 10⁹ = 1,000,000,000

mega- M 10⁶ = 1,000,000 megaton (Mt)

kilo- k 10³ = 1,000 kilometre (km)

hecto-, hect- h 10² = 100 hectare (ha)

deca-, dec- da 10 = 10 decastere (das)

1

deci- d 10^-1 = 0.1 decigram (dg)

centi-, cent- c 10^-2 = 0.01 centimetre (cm)

milli- m 10^-3 = 0.001 millilitre (ml)

micro-, micr- μ 10^-6 = 0.000001 microgram (μg)

nano- n 10^-9 = 0.000000001

pico- p 10^-12 = 0.000000000001

femto- f 10^-15 = 0.000000000000001

atto- a 10^-18 = 0.000000000000000001

*The metric system of bases and prefixes has been applied to many other units, such as decibel (0.1 bel), kilowatt (1,000 watts), megahertz (1,000,000 hertz), and microhm (one-millionth of an ohm).