Alcohol Units Calculator (UK)

How the Alcohol Units Calculator Works

In the UK, alcohol is measured in units, where one unit equals 10 ml (8 g) of pure alcohol — the amount an average adult can process in roughly an hour. Because drinks vary so much in size and strength, “one drink” is rarely one unit. This calculator works out the units in any drink from its volume and ABV (alcohol by volume), then multiplies by how many you have in a week to compare against the 14-unit low-risk guideline.

The Formula

Units come straight from the volume and strength of the drink:

Units = (ABV % × volume in ml) ÷ 1000

The division by 1,000 converts the ABV percentage and millilitres into the number of 10 ml units of pure alcohol. To get a weekly total, multiply the units per drink by the number of drinks you have each week.

Worked Example

For a typical pint (568 ml) of beer at 4.5% ABV, drunk 7 times a week:

• Units per pint = (4.5 × 568) ÷ 1,000 = 2.56 units
• Weekly units = 2.56 × 7 = 17.9 units
• That is 3.9 units over the 14-unit guideline

Units in Common Drinks

Drink	Volume	ABV	Units
Single spirit shot	25 ml	40%	1.0
Small glass of wine	125 ml	13%	1.6
Pint of beer	568 ml	4.5%	2.6
Large glass of wine	250 ml	13%	3.3
Bottle of wine	750 ml	13%	9.8

Drinking Within the Guidelines

• 14 units per week is the UK low-risk limit for both men and women, set by the Chief Medical Officers.
• Spread your drinking over three or more days rather than concentrating it, and have several alcohol-free days each week.
• Bigger and stronger drinks carry more units — a large glass of strong wine can be three units on its own.
• Track over a week, since a single heavy night can put you over the weekly limit by itself.

This calculator is for general guidance and education, not medical advice. The 14-unit figure is a population guideline; if you are concerned about your drinking, speak to a doctor or a service such as your national health provider.