Alcohol Units Calculator

An alcohol unit is a standardized measure used to track how much pure alcohol you consume, making it easy to compare drinks across different types and strengths.

The Formula:

Units = (Volume in mL × ABV%) / 1000, where ABV is alcohol by volume, the strength printed on the label

One unit = 10 mL (8g) of pure alcohol (UK standard)

Note: The US “standard drink” = 14g of pure alcohol = 1.75 UK units.

Worked Examples:

• Pint of 4% beer (568 mL): Units = (568 × 4) / 1000 = 2.3 units
• Medium glass of wine, 175 mL at 13%: Units = (175 × 13) / 1000 = 2.3 units
• Single shot of spirits, 25 mL at 40%: Units = (25 × 40) / 1000 = 1.0 unit
• Large wine, 250 mL at 14%: Units = (250 × 14) / 1000 = 3.5 units

UK pub glass sizes are 125 mL small, 175 mL medium and 250 mL large, which is what the dropdown above uses. A large glass is a third of a bottle, so three of them finish it. The second example is a medium, not a small, and it is worth noticing that it carries the same units as a whole pint of beer.

UK Chief Medical Officers’ Low-Risk Guidelines (2016):

• Men and women: no more than 14 units per week
• Spread over 3 or more days if you drink that much, rather than all at once
• Several drink-free days a week, which is their advice for cutting down

The World Health Organization sets no weekly figure at all. Its position since 2023 is that no level of drinking is safe for health, which is a stricter line than any unit count.

Common Drink Unit Reference:

Practical Tips:

• Tracking units beats counting “drinks”, because a large wine is twice a small one and the word covers both
• Your liver processes roughly 1 unit per hour regardless of food, coffee, or sleep
• High-strength craft beers at 7 to 10% ABV can deliver 4+ units per can

About the calorie figure

One unit is 10 mL of pure ethanol, which weighs 7.89 g at 0.789 g/mL. Ethanol carries about 7 kcal per gram, so a unit is roughly 56 kcal. That is what this calculator reports.

It is the alcohol calories only. A pint of 5% lager is 2.8 units, so 159 kcal of ethanol, but the actual pint is closer to 180 to 220 kcal once the residual carbohydrate is counted. Dry spirits with a zero-calorie mixer land near the ethanol figure; beer, cider, sweet wine and anything with juice or syrup run well above it. Treat the number as a floor.

Session or week?

The unit count here is for whatever you enter in the drinks box, so it is normally one session. The comparison against 14 units is the weekly guideline, shown so you can see what fraction of the week’s allowance a single evening uses. If you want a weekly total, enter the whole week’s drinks.