Welcome to British volume, where a pint is twenty fluid ounces, a gill is a proper teacup, and a hogshead is not a medieval tavern punishment but enough wine to fill some 325 bottles. Before 1824 the country ran two different gallons at once, one for wine and a larger one for ale, and the difference was entirely deliberate.
Acre-Foot
One foot of water spread over one acre, being twelve acre-inches, and the standard unit of reservoir capacity and water allocation.
43,560 cubic feet = 1,233,482 litres = 271,328 imperial gallons
Acre-Inch
One inch of water spread over one acre, being the working volume of irrigation and land drainage.
3,630 cubic feet = 102,790 litres = 22,611 imperial gallons
Anker
A small Dutch cask of about 38 litres, sized so that a single person could carry it, and the standard vessel of the Georgian contraband trade.
10 wine gallons = 37.85 litres (8.3 imperial gallons)
Barrel
The reference cask of the British brewing trade, holding 36 imperial gallons and anchoring the entire cask hierarchy.
36 imperial gallons = 163.66 litres
Boll
The principal Scots dry measure for grain, holding four firlots, and the unit in which rents and stipends were commonly paid.
Approx. 145 litres for wheat; larger for oats and barley
Bushel (bu)
A traditional dry volume measure equal to 8 gallons used for agricultural goods.
36.37 litres
Centilitre (cl)
One hundredth of a litre, and the customary labelling unit for European wine and spirit bottles.
10 millilitres = 0.01 litres
Cubic Inch (cu in)
The volume of a cube one inch on each side, and the dimension in which English liquid measures were legally defined.
16.387 millilitres
Firkins
A quarter of a barrel equal to 9 imperial gallons, still utilised for cask ales.
9 imperial gallons = 40.91 litres
Firlot
A quarter of a Scots boll, and the everyday working measure of the Scottish grain market.
Approx. 36 litres for wheat; larger for oats and barley
Fluid Drachm (fl dr)
One eighth of an imperial fluid ounce, used by apothecaries and chemists for compounding liquid medicines.
3.5516 millilitres
Fluid Ounce
One-twentieth of an imperial pint, distinctly larger than its US fluid ounce counterpart.
28.41 millilitres
Gallon (gal)
The definitive imperial fluid measure standard equal to 4 quarts, still used for UK fuel efficiency metrics.
4.54609 litres
Gill (gi)
One-quarter of a pint, traditionally used for measuring spirits and pub pour sizes.
142 millilitres
Gowpen
The hollow formed by two cupped hands, and the quantity they will hold.
Approx. 0.9–1.1 litres, varying with the hands
Hogshead
A large traditional bulk shipping cask typically holding 54 gallons for wine and beer.
245.49 litres
Kilderkin
An 18-gallon cask volume representing exactly half of a standard beer barrel.
81.83 litres
Minim
The smallest fluid volume block in apothecary tracking, historically roughly one drop of medicine.
0.059 millilitres
Peck (pk)
A traditional dry volume market unit equal to 2 gallons for orchard fruits.
9.09 litres
Pin
Four and a half imperial gallons, being half a firkin, and the smallest standard cask in the British brewing trade.
4.5 imperial gallons = 20.46 litres = 36 pints
Pinch
As much of a dry substance as can be taken up between the thumb and forefinger.
Conventionally 1/8 teaspoon = approx. 0.6 millilitres
Pint (pt)
20 fluid ounces. The iconic pub baseline fluid measure for British draught beer.
568.26 millilitres
Puncheon
An 84-gallon wide-bellied traditional bulk shipping cask used for rum and wine storage.
381.87 litres
Schooner
Two thirds of an imperial pint, and the newest legal measure for draught beer in Britain.
2/3 imperial pint = 379 millilitres
Scots Pint
Scotland’s own pint, holding roughly 1.7 litres, or about three imperial pints. Its physical standard was the Stirling Jug, held by the burgh of Stirling.
Approx. 1.696 litres = 2.98 imperial pints