How this calculator works
This calculator estimates the number of UK alcohol units in a drink from its volume and strength (%ABV), then multiplies that by how many drinks you have to give an occasion total and a weekly total. It uses the UK Chief Medical Officers' definition of a unit and their low-risk drinking guideline for comparison.
These are estimates for general information, not medical advice. A UK unit is a precise measure of pure alcohol content, but the health guideline it is compared against is a population-level, low-risk target — it does not mean any specific amount of drinking is safe for you personally, and it does not account for your body weight, health conditions, medications, or how your particular body processes alcohol. If you have concerns about your drinking, or about someone else's, talk to a doctor or a service such as Drinkaware or your national health service.
The formula
UK units = (volume in mL × %ABV) ÷ 1,000One UK unit is defined as 10 mL, or about 8 grams, of pure ethanol. The UK Chief Medical Officers' guideline is to drink no more than 14 units a week on a regular basis, and, for anyone who does drink that much, to spread it over 3 or more days rather than in one or two heavy sessions.
Worked example: a pint of 4% beer
- A pint is 568 mL, at 4% ABV.
- Units = (568 × 4) ÷ 1,000 = 2,272 ÷ 1,000 ≈ 2.3 units.
- Six pints like this in a week: 2.3 × 6 ≈ 13.6 units — close to, and commonly rounded to, the 14-unit weekly guideline.
- A 125 mL small glass of 12% wine, by contrast, is (125 × 12) ÷ 1,000 = 1.5 units — almost exactly half a pint of 4% beer.
Frequently asked questions
Does staying under 14 units a week mean my drinking is safe?
No. The 14-unit guideline describes a lower-risk level for the general population, not a proven-safe amount. Alcohol carries some health risk at any level of regular consumption; the guideline is a way to reduce that risk, not eliminate it.
Why does the guideline say to spread drinking over 3 or more days?
Concentrating a week's worth of units into one or two sessions (binge drinking) carries additional short-term risks — accidents, injuries, and acute alcohol poisoning — beyond the risks of the same total spread over more days.
Is the 14-unit guideline the same for men and women?
Yes, in the current UK guidance. This is a change from older UK advice, which set a higher limit for men; the Chief Medical Officers now recommend the same 14-unit guideline for both sexes.
How is a UK unit different from a US standard drink?
A UK unit is 10 mL (about 8 g) of pure alcohol; a US standard drink is defined as 14 g. The two measures are not interchangeable — see the standard drink calculator to convert between countries' definitions.
Does this calculator tell me if I'm drinking too much?
It only does arithmetic: units from volume and strength, and a comparison to a public health guideline. It cannot assess your personal risk. If you are worried about your own or someone else's drinking, that conversation is best had with a doctor or a dedicated alcohol support service.