How UK alcohol units work

A UK alcohol unit is defined as 10 ml (8 g) of pure alcohol. The formula is straightforward:

The formula

Units = (volume in ml × ABV%) ÷ 1,000

Example: a pint of 4% lager = (568 × 4) ÷ 1,000 = 2.27 units

This is the same formula the NHS uses. The tricky part is that serving sizes in pubs and bars vary — a "large" wine can be 175 ml or 250 ml depending on the venue, and craft beers often run 6-8 % ABV rather than the 4-5 % assumed in standard guidance.

NHS low-risk guideline — 14 units per week

Since 2016, the NHS Chief Medical Officers' guidance has been the same for men and women: no more than 14 units per week, spread over three or more days with several drink-free days. Previously, men were allowed 21 units and women 14.

14 units per week is roughly equivalent to:

The guideline is based on keeping the risk of alcohol-related health problems low — not eliminating it entirely. The CMOs are clear that there is no "safe" level of drinking.

Alcohol calories — why they are invisible in most trackers

Alcohol contains 7 kcal per gram — nearly as energy-dense as fat (9 kcal/g) and almost double protein or carbohydrate (4 kcal/g). A pint of 5 % lager contains roughly 240 kcal. A large glass of wine is around 190 kcal. A double gin and tonic with regular tonic clocks in at roughly 170 kcal.

Most food-tracking apps handle alcohol poorly. They may log the drink but not the post-pub kebab, the reduced inhibition around snacking, or the next-day reduction in activity. The real calorie cost of a heavy drinking session is typically 1.5-2x the alcohol calories alone.

Common drinks in units and calories

Pint of lager (4%) 2.3 units · ~180 kcal
Pint of lager (5%) 2.8 units · ~240 kcal
Large wine 250 ml (13%) 3.3 units · ~190 kcal
Small wine 175 ml (13%) 2.3 units · ~135 kcal
Single spirit 25 ml (40%) 1.0 units · ~120 kcal With regular tonic
Double spirit 50 ml (40%) 2.0 units · ~180 kcal With regular tonic
Bottle of beer 330 ml (5%) 1.7 units · ~150 kcal
Can of cider 440 ml (4.5%) 2.0 units · ~200 kcal

FAQ

How many units are in a pint of lager?
A pint of regular-strength lager (4 % ABV) contains 2.3 units. A stronger pint at 5 % ABV contains 2.8 units. A single pint of 5 % lager uses up 20 % of the NHS weekly guideline of 14 units.
Why does alcohol have so many calories?
Alcohol contains 7 calories per gram — almost as energy-dense as fat (9 cal/g) and nearly double carbohydrate or protein (4 cal/g). On top of that, alcoholic drinks often contain sugar from mixers, fruit juice, or residual sugars in wine and beer. A night of four pints can easily add 800 to 1,000 kcal.
What is the NHS low-risk guideline?
The NHS recommends no more than 14 units per week for both men and women, spread over three or more days. This replaced the older daily limits in 2016. 14 units is roughly equivalent to 6 pints of 4 % lager, 6 medium glasses of 13 % wine, or 14 single measures of spirits.