yotta  Y  10^{24}  Extremely
large 
zetta  Z  10^{21}  
exa  E  10^{18}  
peta  P  10^{15}  
tera  T  10^{12}  
giga  G  10^{9}  
mega  M  10^{6}  
kilo  k  10^{3}  
hecto  h  10^{2}  
deca  da  10^{1}  
 
 
10^{0} (=1) 
 
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}  
atto  a  10^{18}  
zepto  z  10^{21}  
yocto  y  10^{24}  Extremely
small 
Name  Symbol  Measure  Named After 
metre  m  length  
kilogram^{[*]}  kg  mass  
second  s  time  
ampere  A  electric current  Ampère 
kelvin  K  thermodynamic temperature  Kelvin 
mole  mol  amount of substance  
candela  cd  luminous intensity 
Name  Symbol  Quantity  Named After 
hertz  Hz  frequency  Hertz 
radian  rad  angle (dimensionless) 

steradian  sr  solid angle (dimensionless) 

newton  N  force, weight  Newton 
pascal  Pa  pressure, stress  Pascal 
joule  J  energy, work, heat  Joule 
watt  W  power, radiant flux  Watt 
coulomb  C  electric charge or quantity of electricity  Coulomb 
volt  V  voltage, electrical potential difference, electromotive force  Volta 
farad  F  electrical capacitance  Faraday 
ohm^{[*]}  Ω  electrical resistance, impedance, reactance  Ohm 
siemens  S  electrical conductance  Siemens 
weber  Wb  magnetic flux  Weber 
tesla  T  magnetic field strength, magnetic flux density  Tesla 
henry  H  electrical inductance  Henry 
degree Celsius  °C  temperature relative to 273.15 K  Celsius 
lumen  lm  luminous flux  
lux  lx  illuminance  
becquerel  Bq  radioactivity (decays per unit time)  Becquerel 
gray  Gy  absorbed dose (of ionizing radiation)  Gray 
sievert  Sv  equivalent dose (of ionizing radiation)  Sievert 
katal  kat  catalytic activity  
bel 
B 
ratio of values 
Bell 
KHz 
You mean kHz 
khz 
You mean kHz 
meter 
You mean metre 
liter* 
You mean litre 
mhz 
You mean MHz 
mL 
You mean ml (there was no Mr./Dr. Litre). In Europe mℓ is printed on products / packaging 
MS 
You mean ms, most likely, for
milliseconds. megasiemens would be unusual 
MG 
You mean mg, for milligrams 
MCG 
You mean µg 
mil 
You mean a millimetre, not
1/1000" 
M 
You mean m, metres. As in 20m or
160m (amateur radio bands) 
CM 
You mean cm, centimetres. As in 70cm or 23cm (amateur radio bands) 
MF 
You mean µF 
MMF 
You mean pF 
db or DB 
You mean dB 
undoubtedly more to follow :) 