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Alcohol Units Calculator

This alcohol units calculator adds up the alcohol in up to five drinks and tells you the total in UK alcohol units, the calories, and how many standard drinks that equals. Pick a drink type — beer, wine, spirits, cider or cocktail — enter the volume in millilitres and the ABV percentage, and the calculator works out each drink separately and then totals them, so you can see exactly where the units are coming from.

One UK alcohol unit is 10 ml of pure alcohol, which is 8 grams. The UK low-risk drinking guideline is no more than 14 units a week, spread over at least three days. That is roughly six pints of 4% beer or six medium glasses of 12% wine in a week — and a single large glass of wine or a pint of strong beer can hold more units than most people expect. Knowing your units is the first step to staying inside the guideline, and this calculator makes the maths instant.

How it works

A UK alcohol unit is defined as 10 millilitres of pure alcohol. That is the same as 8 grams of alcohol, which is also what many countries call one standard drink. The number of units in a drink depends on only two things: how much liquid there is, and how strong it is. A small glass of strong spirits can hold the same units as a large glass of weak beer, which is why guessing from the size of the glass alone is so unreliable.

How the calculator works. For each drink, pick a type. Each type fills in a typical ABV and a typical calorie figure: beer 5% and 43 kcal per 100 ml, wine 12% and 83 kcal per 100 ml, spirits 40% and 231 kcal per 100 ml, cider 4.5% and 45 kcal per 100 ml, and cocktail 15% and 90 kcal per 100 ml. Then adjust the volume and the ABV to match the drink in front of you — the ABV is printed on every bottle and can. The calculator multiplies volume by ABV and divides by 1,000 to get the units, and works out the calories from the volume. It shows a breakdown for each drink, then totals the units, the calories, and the number of standard drinks (one standard drink equals one unit).

The 14-unit guideline. The UK Chief Medical Officers advise keeping to no more than 14 units a week, spread over at least three days, with several drink-free days. That is about six pints of 4% beer, or six 175 ml glasses of 13% wine, across a week. The guideline is the same for men and women. Regularly drinking more than 14 units a week raises the risk of liver disease, high blood pressure, stroke, several cancers and accidents, and the risk rises steadily with every extra unit — there is no safe threshold, only lower and higher risk.

Tips for using this calculator well. Measure honestly: a "glass of wine" at home is often 250 ml, not the 125 ml or 175 ml served in a bar, and that doubles the units. Check the ABV — beers range from under 3% to over 8%, and the difference between a 4% and a 6% pint is a whole extra unit. If you are comparing an evening out with the weekly guideline, add every drink, including the ones you had before dinner. And remember that units measure alcohol, not intoxication: how drunk you feel also depends on your weight, how much you have eaten, and how fast you drink.

Worked example

Here is a worked example, so you can check the maths yourself.

Step 1: One drink — a 500 ml bottle of beer at 5% ABV.
Step 2: Work out the units. Units = volume × ABV ÷ 1,000, so 500 × 5 ÷ 1,000 = 2,500 ÷ 1,000 = 2.5 units.
Step 3: Work out the calories. Beer has about 43 kcal per 100 ml, so 500 × 43 ÷ 100 = 215 calories.
Step 4: Work out the standard drinks. One unit equals one standard drink (8 g of alcohol), so 2.5 units is 2.5 standard drinks.
Step 5: Compare with the weekly guideline of 14 units. This one bottle is 2.5 out of 14 — about a sixth of the week's limit.

Try it yourself: add one drink, choose Beer, enter 500 ml and 5% ABV, and press Calculate. The tool gives exactly the same result — 2.5 units · about 215 calories · 2.5 standard drinks.

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