This reference sheet provides information about and tools for converting between U.S. customary and metric systems of measurement, including:
1. Conversion Calculators and Apps
The U.S. customary system of measurement originated in methods used by England before the United States became independent. Unlike most of the world that uses the metric system, the U.S. still uses this system for everyday measurements. Knowing how to convert between the two systems allows for better comprehension of instructions, weights, recipes, and distances, among other everyday information.
Today, conversion calculators are widely available on the internet and as mobile apps and perform conversions between units quickly and easily. This Conversion Calculator is one such resource. To understand how to perform these conversions yourself, read on!
2. U.S. Customary Measures
The tables below show common U.S. customary units of measurement for length, area, mass (weight), volume, and temperature.
|
Length
|
|---|
|
Unit
|
Abbreviation
|
Common Equivalent Measures
|
|
inch
|
in
|
|
|
foot
|
ft
|
1 ft = 12 in
|
|
yard
|
yd
|
1 yd = 3 ft
|
|
mile
|
mi
|
1 mi = 5,280 ft
1 mi = 1,760 yd
|
|
Area
|
|---|
|
Unit
|
Abbreviation
|
Common Equivalent Measures
|
|
square inch
|
in²
|
|
|
square foot
|
ft²
|
1 ft² = 144 in²
|
|
square yard
|
yd²
|
1 yd² = 9 ft²
|
|
square mile
|
mi²
|
1 mi² = 640 acres
|
|
acre
|
|
1 acre = 43,560 ft²
|
|
Mass (weight)
|
|---|
|
Unit
|
Abbreviation
|
Common Equivalent Measures
|
|
ounce
|
oz
|
|
|
pound
|
lb
|
1 lb = 16 oz
|
|
short ton
|
|
1 ton = 2,000 lb
|
|
Volume
|
|---|
|
Unit
|
Abbreviation
|
Common Equivalent Measures
|
|
teaspoon
|
tsp
|
|
|
tablespoon
|
Tbsp
|
1 Tbsp = 3 tsp
|
|
cubic inch
|
in³
|
|
|
fluid ounce
|
fl oz
|
1 fl oz = 2 Tbsp
|
|
cup
|
c
|
1 c = 16 Tbsp
1 c = 8 fl oz
|
|
pint (liquid)
|
pt
|
1 pt = 16 fl oz
1 pt = 2 c
|
|
quart (liquid)
|
qt
|
1 qt = 4 c
1 qt = 2 pt
|
|
gallon
|
gal
|
1 gal = 128 fl oz
1 gal = 4 qt
|
|
cubic foot
|
ft³
|
1 ft³ = 1,728 in³
|
|
cubic yard
|
yd³
|
1 yd³ = 27 ft³
|
|
Temperature
|
|---|
|
Unit
|
Abbreviation
|
|
degree Fahrenheit
|
°F
|
3. Converting from U.S. Customary Measures to Metric
To convert from U.S. customary measures to metric on your own, multiply the numerical value of the units in the When You Know column by the approximate unit conversion factor found in the Multiply By column.
-
EXAMPLE
|
When You Know
|
Multiply By
|
To Find
|
|
20 yards
|
0.91
|
approximately 18.2 meters
|
3a. Length
|
When You Know
|
Multiply By
|
To Find
|
|
inch (in)
|
2.54
|
centimeter (cm)
|
|
foot (ft)
|
30.48
|
centimeter (cm)
|
|
yard (yd)
|
0.91
|
meter (m)
|
|
mile (mi)
|
1.61
|
kilometer (km)
|
3b. Area
|
When You Know
|
Multiply By
|
To Find
|
|
square inch (in²)
|
6.45
|
square centimeter (cm²)
|
|
square foot (ft²)
|
0.09
|
square meter (m²)
|
|
square yard (yd²)
|
0.84
|
square meter (m²)
|
|
square mile (mi²)
|
2.59
|
square kilometer (km²)
|
|
acre
|
0.41
|
hectare (ha)
|
3c. Mass (Weight)
|
When You Know
|
Multiply By
|
To Find
|
|
ounce (oz)
|
28.35
|
gram (g)
|
|
pound (lb)
|
0.45
|
kilogram (kg)
|
|
short ton
|
0.91
|
metric ton (t)
|
3d. Volume
|
When You Know
|
Multiply By
|
To Find
|
|
teaspoon (tsp)
|
4.93
|
milliliter (mL)
|
|
tablespoon (Tbsp)
|
14.79
|
milliliter (mL)
|
|
cubic inch (in³)
|
16.39
|
milliliter (mL)
|
|
fluid ounce (fl oz)
|
29.57
|
milliliter (mL)
|
|
cup (c)
|
0.24
|
liter (L)
|
|
pint, liquid (pt)
|
0.47
|
liter (L)
|
|
quart, liquid (qt)
|
0.95
|
liter (L)
|
|
gallon (gal)
|
3.79
|
liter (L)
|
|
cubic foot (ft³)
|
0.03
|
cubic meter (m³)
|
|
cubic yard (yd³)
|
0.76
|
cubic meter (m³)
|
3e. Temperature
|
When You Know
|
Multiply By
|
To Find
|
|
degree Fahrenheit (°F)
|
subtract 32, then divide by 1.8
|
degree Celsius (°C)
|
|
degree Fahrenheit (°F)
|
subtract 32, divide by 1.8, add 273.15
|
Kelvin (K)
|
4. Converting from Metric to U.S Customary Measures
Using the same approach, you can convert from metric to U.S. customary measures by using this set of tables. Again, multiply the numerical value of the units in the When You Know column by the approximate unit conversion factor found in the Multiply By column.
4a. Length
|
When You Know
|
Multiply By
|
To Find
|
|
millimeter (mm)
|
0.04
|
inch (in)
|
|
centimeter (cm)
|
0.39
|
inch (in)
|
|
meter (m)
|
3.28
|
foot (ft)
|
|
meter (m)
|
1.09
|
yard (yd)
|
|
kilometer (km)
|
0.62
|
mile (mi)
|
4b. Area
|
When You Know
|
Multiply By
|
To Find
|
|
square centimeters (cm²)
|
0.16
|
square inch (in²)
|
|
square meter (m²)
|
1.20
|
square yard (yd²)
|
|
square kilometer (km²)
|
0.39
|
square mile (mi²)
|
hectare (ha)
(10,000 m²)
|
2.47
|
acre
|
4c. Mass (Weight)
|
When You Know
|
Multiply By
|
To Find
|
|
gram (g)
|
0.04
|
ounce (oz)
|
|
kilogram (kg)
|
2.20
|
pound (lb)
|
metric ton
(1,000 kg)
|
1.10
|
short ton
|
4d. Volume
|
When You Know
|
Multiply By
|
To Find
|
|
milliliter (mL)
|
0.03
|
fluid ounce (fl oz)
|
|
milliliter (mL)
|
0.06
|
cubic inch (in³)
|
|
liter (L)
|
2.11
|
pint, liquid (pt)
|
|
liter (L)
|
1.06
|
quart, liquid (qt)
|
|
liter (L)
|
0.26
|
gallon (gal)
|
|
cubic meter (m³)
|
35.31
|
cubic foot (ft³)
|
|
cubic meter (m³)
|
1.31
|
cubic yard (yd³)
|
4e. Temperature
|
When You Know
|
Multiply By
|
To Find
|
|
degree Celsius (°C)
|
multiply 1.8, then add 32
|
degree Fahrenheit (°F)
|
|
Kelvin (K)
|
subtract 273.15
|
degree Celsius (°C)
|
