D SI Units and Conversions

Official Conversions

Official NIST

Below is a table of conversion factors (source). Bold values indicate exact conversion values. Units in the first column are generally not used in NIST publications except those that are italicized.

Convert from to Multiply by
ångström Å nanometer nm 1.0E-01
astronomical unit au meter m 1.495979E+11
atmosphere, standard atm pascal Pa 1.01325E+05
bar bar pascal Pa 1.0E+05
cubic inch in3 cubic meter m3 1.638706E-05
cubic yard yd3 cubic meter m3 7.645549E-01
cup (US)
milliliter mL 2.365882E+02
day d second s 8.64E+04
degree (angle) ° radian rad 1.745329E-02
electronvolt eV joule J 1.602177E-19
fluid ounce (US) fl oz milliliter mL 2.957353E+01
foot ft meter m 3.048E-01
gallon (US) gal liter L 3.785412
hour h second s 3.6E+03
inch in centimeter cm 2.54
kelvin K degree Celsius °C t/°C = t/K - 273.15
kilocalorieth kcalth kilojoule kJ 4.184
knot (nautical mile per hour)
meter per second m/s 5.144444E-01
liter L cubic meter m3 1.0E-03
micron µ meter m 1.0E-06
mile mi kilometer km 1.609344
mile per gallon (US) mpg, mi/gal kilometer per liter km/L 4.251435E-01
mile per hour mi/h kilometer per hour km/h 1.609344
mile, nautical
meter m 1.852E+03
millimeter of mercury mmhg pascal pa 1.333224E+02
millimeter of water mmH2O pascal pa 9.80665
minute min second s 6.0E+01
ounce (avoirdupois) oz kg g 2.834952E-02
parsec pc meter m 3.085678E+16
peck (US) pk liter L 8.809768
pint (US liquid) liq pt liter L 4.731765E-01
pound (avoirdupois) lb kilogram kg 4.535924E-01
pound-force per square inch psi; lbf/in2 pascal Pa 6.894757E+03
quart (US liquid) liq qt liter L 1.101221
tablespoon
milliliter mL 1.478676E+01
teaspoon
milliliter mL 4.928922
ton, short (2000 lb)
kilogram kg 9.071847E+02
torr Torr pascal Pa 1.333224E+02
yard yd3 meter m 9.144E-01
degree Fahrenheit (temperature) °F degree Celsius °C t/°C = (t/°F - 32)/1.8
degree Fahrenheit (temperature) °F kelvin K t/K = (t/°F + 459.67)/1.8
degree Celsius (temperature) °C kelvin K t/K = t/°C + 273.15
degree Celsius (temperature) °C degree Fahrenheit (temperature) °F t/°F = (t/C × 1.8) + 32