SI units

Prefixes used in the SI system for SI units

The SI units employs a series of prefixes to indicate decimal fractions or multiples of various units.

Prefix of SI units	Abbreviation	Meaning
Mega	M	106
Kilo	k	103
Deci	d	10-1
Centi	c	10-2
Milli	m	10-3
Micro	µ	10-6
Nano	n	10-9
Pico	p	10-12
Femto	f	10-15

Examples of the uses of these prefixes of the SI units are:

• 1 megameter (Mm) = 1 x 10⁶ m
• 1 kilometer (km) = 1 x 10³ m
• 1 decimeter (dm) = 0.1 m
• 1 centimeter (cm) = 0.01 m
• 1 millimeter (mm) = 0.001 m
• 1 micrometer (µm) = 1 x 10^-6 m
• 1 nanometer (nm) = 1 x 10^-9 m
• 1 picometer (pm) = 1 x 10^-12 m
• 1 femtometer (fm) = 1 x 10^-15 m