Home > Electronic Tutorials > Dictionary of Units/Measurements > UK (Imperial) System of Measurements

Dictionary of Units / Measurements

# UK (Imperial) System of Measurements

## Length

12 inches = 1 foot

3 feet = 1 yard

22 yards = 1 chain

10 chains = 1 furlong

8 furlongs = 1 mile

5280 feet = 1 mile

1760 yards = 1 mile

## Capacity

20 fluid ounces = 1 pint

4 gills = 1 pint

2 pints = 1 quart

4 quarts = 1 gallon (8 pints)

## Troy Weights

24 grains  = 1 pennyweight

20 pennyweights = 1 ounce (480 grains)

12 ounces = 1 pound (5760 grains)

## Apothecaries' Weights

20 grains   = 1 scruple

3 scruples = 1 drachm

8 drachms = 1 ounce (480 grains)

12 ounces = 1 pound (5760 grains)

## Area

144 sq. inches = 1 square foot

9 sq. feet = 1 square yard

4840 sq. yards = 1 acre

640 acres = 1 square mile

## Volume

1728 cu. inches = 1 cubic foot

27 cu. feet   = 1 cubic yard

## Mass (Avoirdupois)

437.5 grains = 1 ounce

16 ounces = 1 pound (7000 grains)

14 pounds   = 1 stone

8 stones   = 1 hundredweight [cwt]

20 cwt      = 1 ton (2240 pounds)

## Apothecaries' Measures

20 minims = 1 fl.scruple

3 fl.scruples = 1 fl.drachm

8 fl.drachms = 1 fl.ounce

20 fl.ounces = 1 pint

The old Imperial (now UK) system was originally defined by three standard measures - the yard, the pound and the gallon which were held in London. They are now defined by reference to the S I measures of the metre, the kilogram and the litre. These equivalent measures are exact.

1 yard = 0.9144 metres - same in US

1 pound = 0.453 592 37 kilograms - same in US

1 gallon = 4.546 09 liters - different in US

Note particularly that the UK gallon is a different size to the US gallon so that NO liquid measures of the same name are the same size in the UK and US systems.

Also that the ton(UK) is 2240 pounds while a ton(US) is 2000 pounds. These are also referred to as a long ton and short ton respectively.