# Metric - US/Imperial Conversion Charts

If you need to convert from Imperial or US Standard units to Metric, or the other way around, one of the tables below should help. Or you can use our Unit Converter

Example 1: Convert 500 millimeters to inches:

500 mm x 0.03937 = 19.7 inches

Example 2: Convert 500 millimeters to feet:

500 mm x 0.03937 = 19.7 inches, and there are 12 inches in a foot, so

19.7/12 = 1.64 feet (or 1 foot and 7.7 inches)

Note: values are accurate to 4 significant digits only.

## Length

Metric   US or Imperial
1 millimeter [mm]   0.03937 in
1 centimeter [cm] 10 mm 0.3937 in
1 meter [m] 100 cm 1.0936 yd
1 kilometer [km] 1000 m 0.6214 mile

US or Imperial   Metric
1 inch [in]   2.54 cm
1 foot [ft] 12 in 0.3048 m
1 yard [yd] 3 ft 0.9144 m
1 mile 1760 yd 1.6093 km
1 int nautical mile 2025.4 yd 1.853 km

## Area

Metric   US or Imperial
1 sq cm [cm2] 100 mm2 0.1550 in2
1 sq m [m2] 10,000 cm2 1.1960 yd2
1 hectare [ha] 10,000 m2 2.4711 acres
1 sq km [km2] 100 ha 0.3861 mile2

US or Imperial   Metric
1 sq inch [in2]   6.4516 cm2
1 sq foot [ft2] 144 in2 0.0929 m2
1 sq yd [yd2] 9 ft2 0.8361 m2
1 acre 4840 yd2 4046.9 m2
1 sq mile [mile2] 640 acres 2.59 km2

## Volume/Capacity

Metric   US Measure Imperial
1 cu cm [cm3]   0.0610 in3
1 cu decimeter [dm3] 1,000 cm3 0.0353 ft3
1 cu meter [m3] 1,000 dm3 1.3080 yd3
1 liter [l] 1 dm3 2.113 fluid pt 1.7598 pt

US Measure Imperial   Metric
1 cu inch [in3] 16.387 cm3
1 cu foot [ft3] 0.02832 m3
1 fluid ounce 1.0408 UK fl oz 29.574 ml
1 pint (16 fl oz) 0.8327 UK pt 0.4732 liters
1 gallon (231 in3) 0.8327 UK gal 3.7854 liters

## Mass

Metric   US or Imperial
1 milligram [mg]   0.0154 grain
1 gram [g] 1,000 mg 0.0353 oz
1 kilogram [kg] 1,000 g 2.2046 lb
1 tonne [t] 1,000 kg 1.1023 short ton
1 tonne [t] 1,000 kg 0.9842 long ton

US or Imperial   Metric
1 ounce [oz] 437.5 grain 28.35 g
1 pound [lb] 16 oz 0.4536 kg
1 stone 14 lb 6.3503 kg
1 hundredweight [cwt] 112 lb 50.802 kg
1 short ton (US)   0.9072 t
1 long ton (UK)   1.0160 t

## Temperature

To convert from Celsius to Fahrenheit, first multiply by 9/5, then add 32.
To convert from Fahrenheit to Celsius, first subtract 32, then multiply by 5/9

(To find out why, visit the Temperature Conversion page)

## History of Measurement

Years ago people came up with standard length measures, but they didn't all agree on one system.

The Imperial System (which uses yards, feet, inches, etc to measure length) was developed over hundreds of years in the UK, then the French developed the Metric System (meters) in 1670, which soon spread through Europe, even to England itself in 1963. But the USA and a few other countries still prefer feet and inches.