# Unit reference

This page lists all available units and prefixes. How to use units is explained on the page [Units](../datatypes/units.md).

## Units

Math.js comes with the following built-in units.

Base                | Unit
------------------- | ---
Length              | meter (m), inch (in), foot (ft), yard (yd), mile (mi), link (li), rod (rd), chain (ch), angstrom, mil
Surface             | m2, sqin, sqft, sqyd, sqmi, sqrd, sqch, sqmil
Volume              | m3, litre (l, L, lt, liter), cc, cuin, cuft, cuyd, teaspoon, tablespoon
Liquid              | volume	minim (min), fluiddram (fldr), fluidounce (fldz), gill (gi), cup (cp), pint (pt), quart (qt), gallon (gal), beerbarrel (bbl), oilbarrel (obl), hogshead, drop (gtt)
Angles              | rad, deg, grad, cycle
Time                | second (s), seconds, minute, minutes, hour (h), hours, day, days
Mass                | gram(g), tonne, ton, grain (gr), dram(dr), ounce (oz), poundmass (lbm, lb, lbs), hundredweight (cwt), stick
Electric current    | ampere (A)
Temperature         | kelvin (K), celsius (degC), fahrenheit (degF), rankine (degR)
Amount of substance | mole (mol)
Luminous            | intensity	candela (cd)
Force               | newton (N), poundforce (lbf)
Binary              | bit (b), byte (B)

Note that all relevant units can also be written in plural form, for example `5 meters` instead of `5 meter` or `10 seconds` instead of `10 second`. 

## Prefixes

The following decimal prefixes are available.

Name    | Abbreviation  | Value
------- | ------------- | -----
deca    | da            | 1e1
hecto   | h             | 1e2
kilo    | k             | 1e3
mega    | M             | 1e6
giga    | G             | 1e9
tera    | T             | 1e12
peta    | P             | 1e15
exa     | E             | 1e18
zetta   | Z             | 1e21
yotta   | Y             | 1e24

Name    | Abbreviation  | Value
------  | ------------- | -----
deci    | d             | 1e-1
centi   | c             | 1e-2
milli   | m             | 1e-3
micro   | u             | 1e-6
nano    | n             | 1e-9
pico    | p             | 1e-12
femto   | f             | 1e-15
atto    | a             | 1e-18
zepto   | z             | 1e-21
yocto   | y             | 1e-24

The following binary prefixes are available.
They can be used with units `bit` (`b`) and `byte` (`B`).

Name        | Abbreviation  | Value
----------- | ------------- | -----
kilo, kibi  | k, Ki         | 1024
mega, mebi  | M, Mi         | 1024^2
giga, gibi  | G, Gi         | 1024^3
tera, tebi  | T, Ti         | 1024^4
peta, pebi  | P, Pi         | 1024^5
exa, exi    | E, Ei         | 1024^6
zetta, zebi | Z, Zi         | 1024^7
yotta, yobi | Y, Yi         | 1024^8