Glossary · Law and labelling
Unit of alcohol
Also written UK unit. Each is a name for the same thing, which is why none of them has an entry of its own.
Definition
The United Kingdom measure of alcohol consumed: one unit is 10 ml, or 8 grams, of pure ethanol. Units are calculated as volume in litres multiplied by ABV.
- Subject
- Law and labelling
- Also written
- UK unit
In more detail
A pint of 6% cider contains about 3.4 units, so cider strength has a large effect on the arithmetic. United Kingdom Chief Medical Officers advise not regularly exceeding 14 units a week, spread over three or more days, and state that the safest approach in pregnancy is not to drink at all.
Related terms
Terms that belong to the same part of the subject, or that this one is routinely confused with.
Law and labelling
Standard drink
A national reference quantity of alcohol used in health guidance. It is not internationally consistent: a United States standard drink contains 14 grams of ethanol against the United Kingdom unit’s 8.
Law and labelling
Alcohol by volume
The proportion of a drink’s volume that is pure ethanol at 20 degrees Celsius, expressed as a percentage. It is the figure labelling law requires on drinks above 1.2 per cent.
Chemistry
Ethanol
The alcohol produced by fermentation and the compound that alcohol by volume measures. It contributes sweetness, warmth and body as well as intoxication.
Where to go next
- Cider glossary — The whole vocabulary, by subject and A–Z.
- Comparisons — Terms that are only really clear when set against the thing they are not.
- Search — Finds terms by their aliases and by their spellings in other languages.
Sources
What this page rests on. Where a source is marked as registered rather than read, CiderHQ is recording that the body is authoritative on the subject without claiming to have worked through the document itself. See our evidence policy for what each state means.
NHS · health authority · passage verified 2026-08-24
The definition CiderHQ’s units calculator implements, read against the page rather than assumed: one UK unit is 10 ml or 8 g of pure ethanol, and units are ABV multiplied by volume in millilitres divided by a thousand — which is exactly the arithmetic in `engine/calculators.ts`.
UK Chief Medical Officers’ low risk drinking guidelines
Department of Health and Social Care · health authority · retrieved 2026-08-24
The guidelines that set the UK 14-unit weekly figure, advise spreading consumption over three or more days, and state that the safest approach in pregnancy is not to drink at all. CiderHQ takes its health framing from here rather than from industry material.