VIAS Encyclopedia provides a collection of tables and definitions commonly needed in science and engineering.

Home General Topics Order of Magnitude - Prefixes
See also: Prefixes for Binary Multiples 
del.icio.us Reddit Facebook StumbleUpon MySpace Twitter

Order of Magnitude - SI Prefixes

The SI system introduced not only unified measurement units but also prefixes to indicated the order of magnitude. These prefixes can be seen as a factor which is applied to the particular unit. For example, km (kilometer) means 1000 meters, or GW (gigawatts) means billions of Watts.

Following is a table of the most often needed prefixes:

SI Prefix Factor
E (exa) 1018    = 1000000000000000000
P (peta) 1015    = 1000000000000000
T (tera) 1012    = 1000000000000
G (giga) 109    = 1000000000
M (mega) 106    = 1000000
k (kilo) 103    = 1000
c (centi) 10-2    = 0.01
m (milli) 10-3    = 0.001
µ (micro) 10-6    = 0.000001
n (nano) 10-9    = 0.000000001
p (pico) 10-12    = 0.000000000001
f (femto) 10-15    = 0.000000000000001
a (atto) 10-18    = 0.000000000000000001

Home General Topics Order of Magnitude - Prefixes

Last Update: 2007-01-21