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Short list of weights & measures commonly used in UK Imperial System & US Customary systems
comprised from Encyclopædia Britannica article. Also see AMOUNTS
unit abbreviation
or symbol
equivalents in other units 
of same system
metric
equivalent
Weight
avoirdupois avdp
ton 2,000 pounds 0.907 metric
hundredweight cwt 100 pounds 45.359 kilograms
pound lb, lb avdp or # 16 ounces 0.454 kilogram
ounce oz, or oz avdp 1/16 of a pound 28.350 grams
Apothecaries (pharmacists) often use different weights for pounds, ounces and drams - ask them
Capacity
        US liquid measures
gallon gal 4 quarts or 8 pints or 128 ounces 3.785 liters
quart qt 2 pints or 32 ounces 0.946 liter
pint pt 1/2 quart or 16 ounces 0.473 liter
fluid ounce fl oz 1/16 of a pint 29.573 milliliters
U.S. dry measures
bushel bu 4 pecks  35.239 liters
peck pk 8 quarts 8.810 liters
quart qt 2 pints 1.101 liter
pint pt 1/2 quart (a pint is half a quart) 0.551 liter
        UK liquid and dry measure
bushel bu 4 pecks 0.036 cubic metre
peck pk 2 gallons 0.0091 cubic metre
gallon gal 4 quarts (compare US gallon) 4.546 liters
quart qt 2 pints (2 pints make 1 quart) 1.136 litres
pint pt
fluid ounce fl oz 1/20 of a pint or 8 fluid drams 28.412 cubic centimetres
fluid dram fl dr  60 minims 3.5516 cubic centimetres
        Length
nautical mile nmi 6,076 feet or 1.151 miles 1,852 metres
mile mi 5,280 feet, 1,760 yards or 320 rods 1.609 kilometres
furlong fur 660 feet, 220 yards or 1/8 mile 201 metres
rod rd 5.50 yard or 16.5 feet 5.029 metres
fathom fth 6 feet or 72 inches 1.829 metres
yard yd 3 feet or 36 inches 0.9144 metre
foot ft or ' 12 inches or 1/3 of a yard 30.48 centimetres
inch in or " 0.083 foot or 0.028 yard 2.54 centimetres
Area
square mile sq mi or mi2 640 acres or 102,400 square rods 2.590 square kilometres
acre 4,840 square yards or 43,560 square feet 0.405 hectare, or 4,047 square metres
square rod sq rd or rd2 30.25 square yards or 0.00625 acre 25.293 square metres
square yard sq yd or yd2 9 square feet or 1,296 square inches 0.836 square metre
square foot sq ft or ft2 144 square inches or 0.111 square yard 0.093 square metre
square inch sq in or in2 0.0069 square foot or 0.00077 square yard 6.452 square centimetres
Volume
cubic yard cu yd or yd3 27 cubic feet or 46,656 cubic inches 0.765 cubic metre
cubic foot cu ft or ft3 1,728 cubic inches or 0.0370 cubic yard 0.028 cubic metre
cubic inch cu in or in3 0.00058 cubic foot or 0.000021 cubic yard 16.387 cubic centimetres
acre-foot ac ft 43,560 cubic feet or 1,613 cubic yards 1,233 cubic metres
board foot bd ft 144 cubic inches or 1/12 cubic foot 2.36 litres
cord cd 128 cubic feet (often firewood) 3.62 cubic metres
1The U.S. uses avoirdupois units as the common system of measuring weight.