C 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