What are the metric units of measurement?

The following table lists the metric base units of measurement and their symbols:

Measurement Metric Base Unit
  length   meter (m)
  mass   gram (g)
  time   second (s)
  current   ampere (A)
  thermodynamic temperature   kelvin (K)
  amount of substance   mole (mol)
  luminous intensity   candela (cd)
  plane angle   radian (rad)
  solid angle   steradian (sr)

Note that the metric symbols, or abbreviations, are neither italicized nor capitalized (except ampere (A) and kelvin (K) which are derived from proper names). The symbols are not followed by a period and do not change in plural form.

The metric symbol is used only when it follows a number; otherwise, it is spelled out:

The 1500 m race, slightly under 1 mile in length, is one

of the most exciting events in track and field. 
International track meets use meters instead of yards as the

standard unit of distance measure.

What do the metric prefixes (kilo, mega, giga, milli, etc.) mean?

All derived units in the metric system are in multiples of ten. The prefixes in the table below, in combination with the basic unit names, provide the multiples in the system, e.g., the unit meter with the prefix kilo- produces kilometer, meaning "1,000 meters."

Prefix Symbol Multiple
deka- da 10
hecto- h 102
kilo- k 103
mega- M 106
giga- G 109
tera- T 1012
deci- d 10-1
Prefix Symbol Multiple
centi- c 10-2
milli- m 10-3
micro- 10-6
nano- n 10-9
pico- p 10-12
femto- f 10-15
atto- a 10-18


Metric Measures and Common Equivalents

Metric Common
Measure Equivalent
Kilometer 0.62137 mile
Meter 39.37 inches
Centimeter 0.3937 inch
Millimeter 0.0394 inch
Hectare 2.471 acres
Are 119.6 sq yards
Centiare 1,550 sq inches
Metric Common
Measure Equivalent
Liter 1.057 quarts
Milliliter 0.034 fluid ounce
Kilogram 2.2046 pound, avdp
Kilogram 2.6795 pound, troy
Gram 0.0353 ounce, avdp
Gram 0.03215 ounce, troy
Milligram 0.01543 grain, avdp


Common Measures and Metric Equivalents

Common Metric
Measure Equivalent
Inch 2.54 centimeters
Foot 0.3048 meter
Yard 0.9144 meter
Rod 5.029 meters
Mile 1.6093 kilometers
Sq inch 6.452 sq centimeters
Sq foot 0.0929 sq meter
Sq yard 0.836 sq meter
Sq rod 25.29 sq meters
Acre 0.4047 hectare
Sq mile 259 hectares
Cu inch 16.39 cu centimeters
Cu foot 0.0283 cu meter
Cu yard 0.7646 cu meter
Cord 3.625 steres
Common Metric
Measure Equivalent
Liquid quart (US) 0.9463 liter
Dry quart (US) 1.101 liters
Quart, imperial 1.136 liters
Gallon (US) 3.785 liters
Gallon, imperial 4.546 liters
Peck (US) 8.810 liters
Peck, imperial 9.092 liters
Bushel (US) 35.24 liters
Bushel, imperial 36.37 liters
Dram, avdp 1.772 grams
Ounce, avdp 28.35 grams
Pound, avdp 0.4536 kg
Grain 0.0648 gram
Ounce, troy 31.103 grams
Pound, troy 0.3732 kg