Alcohol Units Calculator
Calculate alcohol units in any drink from volume and ABV. Compare to UK weekly guidelines.
How to use this tool
- Enter volume and abv in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your alcohol units and the full breakdown beneath it.
UK alcohol units = volume (ml) × ABV% ÷ 1000. UK guidelines recommend no more than 14 units per week for men and women.
⚠ This tool is for general information and education only and is not medical advice. Consult a qualified healthcare professional before making health decisions.
Formula
Alcohol units = Volume (ml) × ABV (%) ÷ 1000
% of UK weekly guideline = (Units ÷ 14) × 100, rounded to the nearest whole number
How it works
This calculator uses the UK definition of one alcohol unit, which equals exactly 10 ml (8 g) of pure ethanol. Multiplying drink volume in millilitres by the alcohol-by-volume percentage and dividing by 1,000 gives the number of units. The result is then compared to the UK Chief Medical Officers' low-risk guideline of no more than 14 units per week.
The formula applies uniformly regardless of drink type; accuracy depends on the stated ABV being correct, which can vary in draught beers and home-poured spirits.
Worked example
- Input: volume = 500 ml (a pint of lager), ABV = 5.0%.
- Units: 500 × 5.0 ÷ 1000 = 2.5 units.
- Weekly guideline percentage: (2.5 ÷ 14) × 100 = 17.86%, rounded to 18%.
Alcohol units: 2.5; percentage of UK weekly guideline: 18%
Common mistakes to avoid
- Using the full bottle volume rather than the amount actually consumed — a 750 ml bottle shared between two people is ~375 ml per person, not 750 ml.
- Rounding ABV to a round number (e.g., 5% for a 5.8% beer) meaningfully understates units across multiple drinks.
- Treating the UK 14-unit weekly guideline as a safe daily allowance; it is spread across several days with alcohol-free days included.
Key terms
- Alcohol unit (UK)
- A standard measure equal to 10 ml (8 g) of pure ethanol, used in the UK to quantify alcohol consumption.
- ABV (Alcohol by Volume)
- The percentage of a drink's total volume that is pure alcohol; e.g., a 5% ABV beer is 5% ethanol by volume.
- UK weekly low-risk guideline
- The UK Chief Medical Officers recommend consuming no more than 14 units of alcohol per week, spread across three or more days.
- Ethanol
- The type of alcohol found in alcoholic beverages; its psychoactive and toxic effects are what the unit system aims to help people track.
Frequently asked questions
- What is a UK alcohol unit?
- One unit contains 10 ml (8 g) of pure ethanol. A pint of 5% lager = 2.84 units; a 175 ml glass of 13% wine ≈ 2.3 units.
- What is the NHS weekly guideline?
- The NHS recommends not regularly drinking more than 14 units per week, spread over 3 or more days with some alcohol-free days.