How to Calculate Alcohol Units: Formula and UK Drinks Table

By Rethink Drink. For UK adults. Reviewed November 2026.

To calculate the units in a drink, multiply its strength (ABV, the % on the label) by its volume in millilitres, then divide by 1,000.

Units = ABV (%) x volume (ml) / 1,000

So a pint (568ml) of 4% beer is 4 x 568 / 1,000 = 2.3 units.

That's the formula the NHS uses. One unit is 10ml (or 8g) of pure alcohol.

Want it done for you? Our free alcohol units calculator adds up your whole week, drink by drink, in a couple of minutes.

If you've done the sums before and the answer surprised you... you're not alone. Many of us pour bigger and drink stronger than we think. We'll come back to that.

In short

• The formula: ABV x millilitres / 1,000 = units.

• One unit is 10ml or 8g of pure alcohol. It's a measure of alcohol, not of drinks.

• Quick examples: a single 25ml shot of 40% spirit is 1 unit. A 175ml glass of 12% wine is 2.1. A pint of 4% beer is 2.3. A 750ml bottle of 13.5% wine is about 10.

• Strength matters as much as size. The same 175ml glass can be 2.1 units or 2.4, depending on the wine.

• The UK guideline is not to regularly drink more than 14 units a week, for men and women.

• The quickest way to add up a week is our free units calculator.

What is a unit of alcohol?

A unit is a way of measuring how much pure alcohol is in a drink.

One UK unit is 10ml, or 8g, of pure alcohol. The NHS describes it as roughly the amount an average adult can process in an hour (it varies from person to person).

That's why "one drink" doesn't tell you much.

A small glass of wine and a pint of strong lager are both "one drink"... but one is 1.5 units and the other is about 3.

Units measure the alcohol, not the glass.

How do I calculate units of alcohol?

Three steps.

1. Find the ABV. It's the percentage on the label or the bottle, for example 4.5% or 13%. Use the number, not the % sign.

2. Find the volume in millilitres. A pint is 568ml. A standard glass of wine is 175ml (pubs also serve 125ml and 250ml). A single spirit measure is 25ml or 35ml.

3. Multiply them, then divide by 1,000.

Let's work some through.

A pint of 4% beer:

4 x 568 = 2,272. Divide by 1,000 = 2.3 units.

A 175ml glass of 13% wine:

13 x 175 = 2,275. Divide by 1,000 = 2.3 units.

A 25ml single of 40% gin:

40 x 25 = 1,000. Divide by 1,000 = 1 unit.

A 750ml bottle of 13.5% wine:

13.5 x 750 = 10,125. Divide by 1,000 = 10.1 units.

A shortcut for bottles: if the size is on the label in litres, just multiply litres by ABV. A 0.75 litre bottle of 12% wine: 0.75 x 12 = 9 units. A 70cl (0.7 litre) bottle of 40% vodka: 0.7 x 40 = 28 units.

How many units are in common UK drinks?

Here are typical UK drinks, worked out with the NHS formula. Strengths vary a LOT between brands, so check the label and do the sum if yours is different (or let the calculator do it).

Units rounded to one decimal place. Typical strengths only; your drink may be stronger or weaker.

Look at the wine rows for a second.

The same 175ml glass is 2.1 units at 12%... and 2.4 at 13.5%. Over a bottle, that's the difference between 9 units and just over 10.

Is a shot 25ml or 35ml?

Either.

In the UK, the law says pubs and bars must sell gin, rum, vodka and whisky in 25ml or 35ml measures (or multiples of them), but not both on the same premises.

So a single at one bar might be 1 unit, and at the next one 1.4. A double is 2 units, or 2.8.

If you're not sure, ask. And at home, there's no measure at all unless you use one.

Why do my units come out higher than I expected?

Often because we guess low. Two reasons.

Our drinks are bigger and stronger than we think. Alcohol Change UK points out that most average beers and lagers are stronger than the 3.5% that older guidance assumed, and the drinks we pour may be larger and stronger than we perceive. The old "half a pint is one unit" rule is out of date.

Home pours aren't measured. Pour 250ml of 12% wine into a big glass at home and that's 3 units, in what feels like "one glass".

When Matt, our co-founder, was drinking heavily, his GP asked him how much he drank. He halved the number...

...Plenty of us do the same thing in our own heads. Doing the actual sum is an honest place to start.

What do my units actually mean?

Once you've got a weekly number, you can compare it with the UK guideline.

The UK Chief Medical Officers advise that, to keep health risks low, it's safest for men and women not to drink more than 14 units a week on a regular basis, spread over three or more days, with several drink-free days.

We've put together a full page on what 14 units a week looks like, in pints, glasses and bottles.

A units total is a useful number. But it can't tell you everything.

It can't tell you whether your body has come to depend on alcohol. And it can't tell you why the number is what it is.

Our units calculator also includes the AUDIT-C, a short set of questions about your drinking. Between the two, you get a clearer starting picture.

What if the number worries me?

First... you've done something useful. A lot of people never look.

If you want to cut down, the NHS has practical tips: set a limit before you start, go for smaller sizes or lower-strength drinks, have something to eat and a glass of water first, and have several drink-free days each week.

Important: if your body depends on alcohol, stopping or cutting down too fast can be dangerous. Speak to your GP (General Practitioner) or local alcohol service before you change anything...

...Getting help from your GP and the NHS explains what to expect from that appointment. Take your units number with you; it helps.

And if you keep setting limits and finding the number creeps back up anyway, that isn't a character flaw. We explain why in Why do I drink every night? and No willpower to stop drinking?

Common questions

How are units of alcohol measured?

By the amount of pure alcohol in the drink. One UK unit is 10ml (8g) of pure alcohol. You work it out from the drink's strength and size: ABV x ml / 1,000.

Is a glass of wine 2 units?

Sometimes. A 175ml glass of 12% wine is 2.1 units. A 125ml glass is 1.5. A 250ml glass is 3. Stronger wines push each of those higher.

How many units are in a bottle of wine?

A 750ml bottle is 9 units at 12%, about 10 at 13.5%, and about 10.5 at 14%.

How many units are in a pint?

About 2 units for a 3.6% pint, 2.3 for a 4% pint, and 3 for a 5.2% pint.

How many units are in 70cl of vodka?

At 40%, a 70cl bottle holds 28 units. That's two weeks' worth of the UK low-risk guideline in one bottle.

Does it matter if it's beer, wine or spirits?

Not to the units. A unit is a unit, whatever it comes in. What changes is how quickly they add up.

If you'd like support from us

Rethink Drink is a UK coaching service built around The Sinclair Method. Our programmes include a consultation with an independent prescriber, who decides whether treatment is suitable. Clinical oversight is provided by consultant psychiatrist Professor Jonathan Chick. Any prescription is dispensed by an independent partner pharmacy. Our coaches work with you, week by week, on everything around it.

And whatever happens, you can talk to someone today. Drinkline, the national alcohol helpline, is free and confidential: 0300 123 1110.

Please look after yourself

This page is here to help you understand your options. It isn't medical advice, and it can't replace a conversation with a doctor who can ask qualifying questions.

Before you change how much you drink or start any medication, speak to your GP or a prescriber.

We really hope this post helps. If you have any questions, you can contact us here.

The Rethink Drink team

Sources

1. NHS. Alcohol units. Last reviewed 27 August 2024. https://www.nhs.uk/live-well/alcohol-advice/calculating-alcohol-units/

2. UK Chief Medical Officers. UK Chief Medical Officers' Low Risk Drinking Guidelines. Department of Health, August 2016. https://assets.publishing.service.gov.uk/media/5a80b7ed40f0b623026951db/UK_CMOs__report.pdf

3. GOV.UK. Weights and measures: the law. Specified quantities. https://www.gov.uk/weights-measures-and-packaging-the-law/specified-quantities

4. Alcohol Change UK. What is a unit of alcohol? Your guide. November 2025. https://alcoholchange.org.uk/blog/what-is-a-unit-of-alcohol-your-mini-guide

5. NHS. Tips on cutting down on alcohol. Last reviewed 9 April 2026. https://www.nhs.uk/live-well/alcohol-advice/tips-on-cutting-down-alcohol/

6. NHS. Alcohol support (Drinkline). Last reviewed 17 August 2026. https://www.nhs.uk/live-well/alcohol-advice/alcohol-support/