Gill (gi)

The gill is a unit of volume equal to a quarter of an imperial pint, or exactly 142.0653125 millilitres. Its symbol is gi. It is five imperial fluid ounces, and it sits between the fluid ounce and the pint in the old British liquid chain. Its name is pronounced with a soft g, so that it sounds like the name Jill, which surprises most readers who meet it only in print.

For most of the twentieth century it governed the British pub. Spirits were served in fractions of a gill, and the fraction varied by region: a sixth of a gill in England and Wales, a fifth in Scotland, and a quarter in Northern Ireland. A traveller ordering the same drink in three cities therefore received three different quantities, all legally correct and all described by the same words.

That system ended in 1995, when the United Kingdom replaced the gill fractions with metric measures of 25 or 35 millilitres, each establishment choosing one and displaying which. The change was less disruptive than it looked, because a fifth of a gill is 28.4 millilitres and a quarter is 35.5, so the new measures sat close to the old ones and the drinks barely changed size.

Cookery kept it longer than the law did. British and Irish recipes written before the 1970s call for a gill of cream, stock or milk, and the quantity is a quarter pint, which is 142 millilitres. Anyone working from an inherited recipe book meets the word regularly, and the conversion is one of the few worth writing on the flyleaf.

The American gill is a different quantity again. It is a quarter of a United States liquid pint, therefore four United States fluid ounces or 118.3 millilitres, about a sixth smaller than the imperial gill. It appears in old American recipes and in the occasional bar manual, and the same caution applies as with the pint: the name says nothing about which system is meant.

Today the gill survives in dialect, in historical writing and in the specifications of glassware sold for period use. It is one of the clearest cases of a unit outliving its own function, kept alive by cookbooks and by the memory of how a drink used to be poured.

One imperial gill equals 142.065 millilitres, 5 imperial fluid ounces, 0.25 imperial pints, or about 1.201 US gills.

Gill conversion table