A pint of weak beer and a small glass of wine can look like very different drinks, but once you convert them into alcohol units the comparison becomes fair. This calculator turns the size and strength of any drink into UK units — the same measure used by the NHS, the World Health Organization, and most European health services — so you can see exactly how much pure alcohol you are consuming and whether your weekly habit sits within the recommended 14-unit limit.
Unlike a BAC calculator, which estimates your moment-to-moment blood concentration, this tool counts standard units. It answers a different question: "How much alcohol am I actually drinking, per drink and per week?" That distinction matters, because the long-term health evidence on alcohol is built around weekly intake, not a single evening.
How to Use
- Enter the Drink Volume in milliliters. Use the size you actually pour — 330 ml for a standard bottle, 500 ml for a large can, and 568 ml for an imperial pint. If you order a pint-and-a-half, type in the real number rather than a "typical" one.
- Set the ABV (Strength) as a percentage. Check the label: most lagers sit at 4–5%, craft IPAs can reach 6–8%, table wine is usually 12–14%, and a single spirit measure is about 40%.
- Type how many of these drinks you have on an average week under Drinks per Week. Be honest — rounding up gives you a more useful picture.
- Read the result card: units per drink, pure alcohol per drink in milliliters, total weekly units, weekly grams of pure alcohol, and whether your weekly total is within the NHS 14-unit guideline.
Swap the numbers to compare drinks. Put in a pint of 4% lager, then a 250 ml glass of 13% wine, then a 35 ml nip of 40% whisky. The volumes look nothing alike; the units tell the real story.
The UK Unit Formula
One UK unit is defined as 10 milliliters (about 8 grams) of pure alcohol. Because alcohol makes up a percentage of the drink's volume, the calculation is deliberately simple:
Units = volume (ml) × ABV% ÷ 1000
Worked example: a 568 ml pint of 4% lager contains 568 × 4 ÷ 1000 = 2.27 units. A standard 175 ml glass of 13% wine contains 175 × 13 ÷ 1000 = 2.28 units. Two drinks that feel wildly different on the menu are, in unit terms, nearly identical.
For weekly intake, multiply units per drink by how often you drink it. Seven pints of 4% lager a week gives 2.27 × 7 = about 15.9 units — just over the NHS low-risk guideline of 14 units spread across the week. The calculator also converts weekly units into grams of pure alcohol (1 unit ≈ 8 g), which is the figure used in most nutrition and public-health databases.
Why Weekly Units Matter
The NHS advises both men and women not to drink more than 14 units a week on a regular basis, and to spread those units over at least three days rather than saving them for one session. Drinking 14 units on a single Friday night is binge drinking, even though the weekly total looks "on budget." Use the drinks-per-week field to model your own rhythm: if you drink twice a week, the calculator shows the per-day average you would need to stay under the line.
Examples
Example 1 — Weekly lager habit. Someone drinks six 500 ml cans of 4.5% lager per week. Each can is 500 × 4.5 ÷ 1000 = 2.25 units; weekly intake is 2.25 × 6 = 13.5 units, which sits just inside the 14-unit NHS guideline, with about 108 g of pure alcohol.
Example 2 — Wine by the glass. A 250 ml large glass of 13.5% restaurant wine is 250 × 13.5 ÷ 1000 = 3.38 units — more than a whole pint. Having two of those on four evenings a week reaches 3.38 × 8 = 27 units, nearly double the guideline. Swapping to a 175 ml glass drops the per-drink figure to 2.3 units.
Example 3 — Spirits at home. A 35 ml nip of 40% whisky is 35 × 40 ÷ 1000 = 1.4 units. Five nips across the week totals 7 units and about 56 g of pure alcohol — a reminder that short measures still add up, especially when the ABV is high.
Example 4 — Comparing a pint and a cocktail. A 568 ml pint of 4% beer is 2.27 units. A 200 ml cocktail mixed at 12% ABV (one spirit plus mixer) is 200 × 12 ÷ 1000 = 2.4 units. The cocktail looks smaller but carries roughly the same alcohol as the pint, and it is usually consumed faster.
FAQ
What is a UK alcohol unit?
A UK unit is exactly 10 milliliters — about 8 grams — of pure alcohol. It is the standard measure used by the NHS to compare drinks of different size and strength, and it is the basis of the 14-units-per-week low-risk drinking guideline.
How do I calculate units from volume and ABV?
Multiply the drink volume in milliliters by the ABV percentage, then divide by 1000. For example, 330 ml of 5% beer is 330 × 5 ÷ 1000 = 1.65 units. This is the same formula the NHS publishes on its alcohol units guidance page.
How many units are in a pint of beer?
It depends on strength. An imperial pint (568 ml) of 4% lager is about 2.3 units; a 5% craft pint is about 2.8 units; and a super-strength 8% pint reaches 4.5 units. Always check the ABV on the can or pump clip.
How many units are in a glass of wine?
A 175 ml glass of 12% wine is about 2.1 units; a 250 ml large glass of 13.5% wine is about 3.4 units; and a standard 750 ml bottle of 12.5% wine totals about 9.4 units. Restaurant "large" glasses are the easiest way to quietly exceed the weekly limit.
What is the NHS 14-unit guideline?
The NHS recommends that regular drinkers do not exceed 14 units per week, spread over at least three days, with several alcohol-free days each week. This calculator flags any weekly total above 14 units so you can adjust pour size, strength, or frequency.
Is this the same as a BAC calculator?
No. A BAC calculator estimates your blood alcohol concentration at a moment in time from weight, sex, and hours since your first drink. This calculator counts standard units per drink and per week — the measure used for long-term health guidance, not for judging whether you are safe to drive.
How many grams of pure alcohol are in a unit?
Approximately 8 grams. Since one unit is 10 ml of ethanol and ethanol's density is about 0.789 g/ml, 10 ml weighs roughly 7.9 g, which public-health guidance rounds to 8 g. Multiply your weekly units by 8 to get weekly grams of pure alcohol.
Disclaimer
This alcohol unit calculator is provided for informational purposes only and is not medical advice. It does not replace guidance from your doctor, nurse, or a licensed health professional, and it is not suitable for diagnosing or managing alcohol-related conditions. Unit estimates depend on the volume and ABV you enter; actual pours and label strengths vary. Never drink and drive, and if you are pregnant, taking medication, or concerned about your drinking, speak to a healthcare professional. If alcohol use feels out of control, contact a free local support service such as your national alcohol helpline.