How to use the alcohol units calculator
- Pick a Drink type for a quick start, or choose Custom drink to enter your own.
- Check the Volume per drink and its unit: ml, cl or US fl oz. Presets fill in both.
- Enter the ABV (%) printed on the label. For US proof, halve it: 80 proof is 40%.
- Set Number of drinks if you had more than one. The results are the total.
- Read UK units, US standard drinks, Pure alcohol and Calories from alcohol. The line underneath compares your total with the weekly NHS limit.
How the calculation works
Pure alcohol in ml is volume × ABV ÷ 100 × number of drinks. The NHS defines one UK unit as 10 ml (8 g) of pure alcohol, so UK units are pure alcohol in ml ÷ 10. Grams are ml × 0.789, the density of ethanol. A US standard drink holds 14 g (NIAAA), a Canadian one 13.45 g and an Australian one 10 g. Calories from alcohol are grams × 7, per the NHS.
Worked example
The page opens with a pint of beer: 568 ml at 4% ABV, one drink. 568 × 4 ÷ 100 = 22.72 ml of pure alcohol, which is 2.3 UK units. In grams that is 22.72 × 0.789 = 17.9 g, or 1.3 US standard drinks (17.9 ÷ 14), and about 125 calories from alcohol. The total is 16% of the 14 weekly units the NHS advises.
Guidelines compared
- UK: the NHS advises no more than 14 units a week on a regular basis, spread over 3 or more days.
- US: the 2025 to 2030 Dietary Guidelines (January 2026) advise consuming less alcohol and no longer give the earlier limits of 1 drink a day for women and 2 for men.
- Canada: the CCSA's 2023 guidance rates 2 standard drinks a week or fewer as low risk.
- Australia: the NHMRC's 2020 guidelines say no more than 10 standard drinks a week and no more than 4 on any one day.
Limits and edge cases
- Results use the strength printed on the label. Home pours are often bigger than bar measures, so measure for accuracy.
- Calories count the alcohol only. Sugar in mixers, cider and liqueurs adds more.
- Volume can be up to 5,000 ml per drink, ABV 0 to 100 and drinks 0.1 to 100. Anything else shows an error.
- This is not a blood alcohol or driving calculator. Never use it to decide whether you can drive.
To see how drinks fit a weight goal, try the Weight Loss Calculator or the Calories Burned Calculator.
Frequently asked questions
How many units are in a pint of beer?
A pint (568 ml) of 4% beer is 2.3 units. A pint of 5.2% lager or cider is 3 units, and a 440 ml can of 4.5% lager is 2 units.
How many units are in a bottle of wine?
A 750 ml bottle at 13.5% is about 10 units. At 12% it is 9 units, and a standard 175 ml glass at 12% is 2.1 units.
How many UK units is one US standard drink?
One US standard drink contains 14 g of pure alcohol, which is about 1.8 UK units. It equals 12 fl oz of 5% beer, 5 fl oz of 12% wine or 1.5 fl oz of 40% spirits.
Why do the UK, US, Canada and Australia give different numbers?
Each country defines a standard drink by a different amount of pure alcohol: 8 g for a UK unit, 10 g in Australia, 13.45 g in Canada and 14 g in the US. The drink is the same, so the count changes.
Can this calculator tell me if I am safe to drive?
No. It does not estimate blood alcohol concentration, which depends on your weight, sex, food and timing. Alcohol impairs driving even at low levels, so if you have been drinking, do not drive.
Sources: NHS; NIAAA; Health Canada; NHMRC.