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 inches 2.5 centimeters cm
ft feet 30 centimeters cm
yd yards 0.9 meters m
mi miles 1.6 kilometers km


Area


Symbol When You Know Multiply By To Find Symbol
in² square inches 6.5 square centimeters cm²
ft² square feet 0.09 square meters
yd² sqaure yards 0.8 square meters
mi² square miles 2.6 square kilometers km²
  acres 0.4 hectares ha


Mass (weight)


Symbol When You Know Multiply By To Find Symbol
oz ounces 28 grams g
lb pounds 0.45 kilograms kg
  short tons
(2000 lb)
0.9 metric ton t


Volume


Symbol When You Know Multiply By To Find Symbol
tsp teaspoons 5 milliliters mL
Tbsp tablespoons 15 milliliters mL
in³ cubic inches 16 milliliters mL
fl oz fluid ounces 30 milliliters mL
c cups 0.24 liters L
pt pints 0.47 liters L
qt quarts 0.95 liters L
gal gallons 3.8 liters L
ft³ cubic feet 0.03 cubic meters
yd³ cubic yards 0.76 cubic meters


Temperature (exact)


Symbol When You Know Multiply By To Find Symbol
°F degrees Fahrenheit subtract 32, multiply by 5/9 degrees Celsius °C

 °F

 degrees Fahrenheit

 subtract 32, multiply by 5/9, add 273.15

Kelvin

 °K


Note: These 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