NIST logo

Common Conversion Factors

Approximate Conversions from U.S. Customary Measures to Metric


Length


Symbol When You Know Multiply By To Find Symbol
in inch 2.54 centimeter cm
ft foot 30.48 centimeter cm
yd yard 0.91 meter m
mi mile 1.61 kilometer km


Area


Symbol When You Know Multiply By To Find Symbol
in² square inch 6.45 square centimeter cm²
ft² square foot 0.09 square meter
yd² square yard 0.84 square meter
mi² square mile 2.59 square kilometer km²
  acre 0.41 hectare ha


Mass (weight)


Symbol When You Know Multiply By To Find Symbol
oz ounce 28.35 gram g
lb pound 0.45 kilogram kg
  short ton
(2000 lb)
0.91 metric ton t


Volume


Symbol When You Know Multiply By To Find Symbol
tsp teaspoon 4.93 milliliter mL
Tbsp tablespoon 14.79 milliliter mL
in³ cubic inch 16.39 milliliter mL
fl oz fluid ounce 29.57 milliliter mL
c cup 0.24 liter L
pt pint, liquid 0.47 liter L
qt quart, liquid 0.95 liter L
gal gallon 3.79 liter L
ft³ cubic foot 0.03 cubic meter
yd³ cubic yard 0.76 cubic meter


Temperature (exact)


Symbol When You Know Multiply By To Find Symbol
°F degree Fahrenheit subtract 32, then 
multiply by 1.8
degree Celsius °C
°F

 degree Fahrenheit

subtract 32, multiply by 1.8, add 273.15

Kelvin

 °K


Note: These approximate conversion factors are published as NIST SP 365, which is a laminated metric conversion card. Copies of this publication can be requested by contacting theSI@nist.gov

*
Bookmark and Share