Base Units

Name Symbol Comment
meter m length
kilogram kg mass
second s time
ampere A electric current
kelvin K thermodynamic temperature
mole mol amount of substance
candela cd luminous intensity

 

Prefixes

Prefix Symbol

Factor

yotta Y

10^{24}

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

deci d

10^-1

centi c

10^-2

milli m

10^-3

micro u

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}

 

Derived Units

Name Symbol Unit Comment
gram g 0.001 kg mass
minute min 60 s time
hour hr 3600. s time
day day 24 hr time
year y 365.24 d time
pound lb 0.45359237 kg mass
ounce oz 1.77185E-3 kg mass
inch in 2.54 cm length
foot ft 12 in length
mile mi 5280 ft length
yard yd 0.9144 m length
nautical_mile n_mi 6080 ft length, nautical mile (UK)
astroUnit AU 1.49598E11 m length, mean earth to sun distance
speed of light c 2.99792E8 m/s velocity
lightsecond cs 2.99792E8 m length
lightminute cmin 60 cs length
lighthour chr 60 cmin length
lightday cday 24 chr length
lightyear cy 9.461E15 m length
acre acre 4840 yd^2 area, acre
hertz Hz 1/s frequency
litre L 10^3/cm^3 volume
newton N m*kg/s^2 force
pound_force lbf 4.44822 N force
dyne dyn 1E-5 N force
pascal Pa N/m^2 pressure, stress
bar bar 1E5 Pa pressure
mmHg mmHg 1.33322E2 Pa pressure, millimeter of mercury
torr torr 1 mmHg pressure
atm atm 760 torr pressure, standard atmosphere
joule J N*m energy, work, heat
electronvolt eV 1.6021892E-19 J energy
calorie cal 4.1868 J energy
Btu Btu 1.05506E3 J energy
watt W J/s power, radiant flux
coulomb C A*s electric charge
volt V J/C electric potential, electromotive force
ohm ohm V/A electric resistance, use this in /ANS
ohm ohms V/A electric resistance
ohm Ohm V/A electric resistance
ohm Ohms V/A electric resistance
siemens S A/V electric conductance
farad F C/V electric capacitance
tesla T V s/m^2 magnetic flux density
weber Wb V*s magnetic flux
henry H V*s/A inductance
radian rad m /m plane angle
degree deg 1.745329E-2 rad plane angle (Pi rad=180 deg)
steradian sr m^2 /m^2 solid angle
lumen lm cd*sr luminous flux
lux lx cd*sr/m^2 illuminance
becquerel Bq 1/s activity (radioactive)
gray Gy J/kg absorbed dose (of radiation)
sievert Sv J/kg dose equivalent (dose equivalent index)
Plancks Const hbar 1.054573E-34 J*s angular momentum