This page features tables and calculators for converting between metric system units
and corresponding English units that are commonly used in the United States.
Here you will find conversion tables for
length,
area,
volume,
weight,
pressure,
energy, and
temperature
units, as well as conversion calculators for length, area, liquid volume, dry volume, weight, pressure, and energy.
Conversion table calculations show approximately three (3) significant figures.
Length Conversion
Metric length units include the meter, the kilometer (1,000 meters),
the decimeter (0.1 meters), the centimeter (0.01 meters), the millimeter
(0.001 meters), the micron (0.000001 meters), the nanometer (0.000000001
or 1e-9 meters), and the angstrom (0.0000000001 or 1e-10 meters).
British and American length units include the foot, the yard (3 feet),
the furlong (660 feet), the mile (5,280 feet), the league
(15,840 feet), and the inch (1/12th foot).
Metric volume units include the liter, the decaliter (10 liters), the
hectoliter (100 liters), the deciliter (0.1 liters), the centiliter
(0.01 liters), the milliliter (0.001 liters), and the microliter (0.000001
liters.
A liter is equivalent to 1 cubic decimeter.
Milliliters and Ounces
Liquid measure units commonly used in the USA include the fluid ounce,
the pint (16 fluid ounces), the quart (32 fluid ounces), the gallon
(128 fluid ounces), and the petroleum barrel (5376 fluid ounces).
A gallon is equivalent to 231 cubic inches.
Metric weight units include the gram, the kilogram (1,000 grams), the
tonne (1,000,000 grams), the carat (0.2 grams), the centigram (0.01
grams), the milligram (0.001 grams), and the microgram (0.000001 grams).
Avoirdupois weight units commonly used in the USA include the pound, the
stone (14 pounds), the short hundredweight (100 pounds), the short ton
(2,000 pounds), the ounce (1/16th pound), the dram (1/256th pound), and
the grain (1/7000th pound).
Metric pressure units include the bar, the millibar (0.001 bars),
and the pascal (0.00001 bars).
One bar is equivalent to 10,200 kilograms per square meter.
The pressure units commonly used in the USA include the inch of mercury
and the atmosphere (29.92 inches of mercury).
One atmosphere is equivalent to 14.7 pounds per square inch.
Metric energy units include the joule, the kilojoule (1000 joules),
and the megajoule (1000000 joules).
The energy units commonly used in the USA include the calorie and
the British Thermal Unit (BTU). A calorie is commonly defined as
the amount of heat energy required to raise the temperature of one gram
of water by one degree Celsius. However, the energy needed for this
task depends on the water's starting temperature. The thermochemical
calorie is defined as exactly 4.184 joules, but several other, slightly
different definitions exist as well.
One calorie is equivalent to 3.088 foot-pounds; one BTU is equivalent to
252 calories. Using this latter definition, one calorie is equal
to 4.187 joules.
Metric temperature units include degrees Celsius and degrees Kelvin
(degrees Celsius plus 273.1). At sea level, the freezing temperature
of water is 0 degrees Celsius and the boiling point of water is 100
degrees Celsius.
The temperature unit commonly used in the USA is Fahrenheit. At sea
level, the freezing temperature of water is 32 degrees Fahrenheit and the
boiling point of water is 212 degrees Fahrenheit.
NIST Metric Information and Conversions
Find a wealth of educational and reference resources about the metric system and its implementation, as well as metric conversion tables and calculators.
The United States and the Metric System
The United States is now the only industrialized country in the world that does not use the metric system as its primary system of measurement.
Learn the history of the metric system and how the United States has been involved with this system since the early 19th century.