Measurement Units

Customary

Length

inch (basic unit)

foot = 12 inches

yard = 3 feet (36 inches)

furlong = 220 yards (660 feet)

mile = 5280 feet ( 1760 yards ) ( 8 furlongs)

* nautical mile 1.1500779 mi. ( ~6076 ft. )

fathom = 6 feet

* rod = 5 1/2 yards

* chain = 22 yards

Volume

Wet

teaspoon = 1/3 tablespoon

tablespoon = 1/2 ounce

ounce = (basic unit)

jigger = 2 ounces

gill = 2 jiggers (4 oz.)

cup = 8 ounces ( 2 gills )

pint = 2 cups ( 16 oz. )

quart = 2 pints (32 oz.)

gallon = 4 quarts (128 oz.)

* (231 cubic inches)

Dry

pint

quart = 2 pints

peck = 8 quarts

bushel = 4 pecks (2150.42 cubic in.)

* Barrel = 105 quarts (varries with material being measured)

Weight

Avoirdupois

dram = 27 & 11/32 grains

ounce = 16 drams (437.5 grains)

pound (lb.) = 16 ounces ( 7000 grains )

hundredweight (cwt.) = 100 pounds

ton = 2000 lbs. (20 cwt.)

* Troy

* ounce ( 480 grains)

* pound = 12 ounces ( 5760 grains )

The above interaction in systems results in the standard joke that an ounce of gold weighs more than an ounce of feathers but a pound of gold weighs less than a pound of feathers. Since gold is weighed in the troy system and feathers in the avoirdupois.

Area

acre = 160 square rods ( 43560 square feet) or (1/640 square mi.)

Metric

Legalized in the US in 1866.

Prefix Multipliers

Factor 10 Exp Name Abreviation
1/1000000000000 -15 femto f
1/1000000000 -12 pico p
1/1000000 -9 nano n
1/1000000 -6 micro µ, (mu)
1/1000 -3 milli m
1/100 -2 centi c
1/10 -1 deci d
1
10 1 deka da
100 2 hecto h
1000 3 kilo k
1000000 6 mega M
1000000000 9 giga G
1000000000000 12 tera T
1000000000000000 15 pita P
1000000000000000 18 exa E

These multipliers occur before the units or the abreviations of the units.

The custom is to not use a period with metric units as is done with customary units. Thus write cm but use in. for the customary units.

Length

m Meter

* (distance traveled by light in 1/299,732.458 seconds)

Volume

l Liter

( cubic decimeter) = (1 dm )3

Weight

g gram

( milliliter of water) ( cubic centimeter of water)

Also:

1 kg

( 1 liter of water )

Also:

T metric ton or long ton (1000 kg)

( cubic meter of water )

Area

a are

( square dekameter)

Usual use is hectare

( 100 m by 100 m ) for hectare

* These items need not be memorized.