Alcohol Unit Calculator
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Calculate units of alcohol in any drink from volume and ABV. Compare to UK and US health guidelines.
Quick answer: One UK alcohol unit equals 10ml (8g) of pure alcohol — a standard 330ml beer at 5% ABV contains 1.65 units. The NHS recommends no more than 14 units per week for both men and women, spread across 3 or more days.
Units of Alcohol
1.65 units
1 UK unit = 10ml (8g) of pure alcohol. UK NHS recommends no more than 14 units per week spread over 3+ days.
📐 Formula
Units = (Volume ml × ABV%) ÷ 1000. Calories ≈ Units × 56 kcal
How to Use the Alcohol Unit Calculator
Select your drink type
Choose beer, wine, spirits, or enter a custom drink. Strength (ABV%) varies significantly — a 3.5% session beer is roughly half the alcohol of a 7% craft IPA of the same volume.
Enter volume and strength
Input the volume in ml and the ABV percentage printed on the label. For a pint of beer: 568ml. For a standard wine glass: 175ml. For a single spirit measure: 25ml (UK) or 35ml (pub).
Add all drinks for the session
Use the multi-drink feature to total a full evening. The calculator adds units cumulatively and shows your weekly total if tracking multiple days.
Check against NHS guidelines
The NHS recommends no more than 14 units per week for both men and women. The calculator flags when you approach or exceed this threshold.
Understanding Alcohol Units
One UK alcohol unit contains 10ml (8g) of pure alcohol — a standardised measure used by the NHS to help people track intake. The formula is simple: divide the volume in ml by 1,000 and multiply by the ABV percentage. A 330ml bottle of 5% lager contains 330 × 5 ÷ 1,000 = 1.65 units. A 250ml large glass of 13% wine contains 250 × 13 ÷ 1,000 = 3.25 units — nearly a quarter of the weekly recommendation in one glass.
The 14-Unit Weekly Limit: What It Looks Like in Practice
14 units per week equates to: 6 pints of average-strength beer (4% ABV), or 10 small glasses of wine (125ml at 12%), or roughly 14 single pub measures of spirits (25ml at 40%). Crucially, the NHS advises spreading these across three or more days and having several alcohol-free days each week — not saving the full 14 units for a single session, which creates acute health risks regardless of the weekly total.
Alcohol and Calories: The Often-Missed Connection
Alcohol contains 7 calories per gram of pure ethanol — almost as calorie-dense as fat (9 cal/g) and nearly double carbohydrates and protein (4 cal/g each). A pint of 5% lager contains approximately 215 calories. A large glass of wine runs 185–250 calories depending on sugar content. These calories carry no nutritional value (no protein, vitamins, or minerals), are metabolised before fat and carbohydrates, and are not captured on many food tracking apps unless manually entered. The average person who drinks moderately may consume 1,000–2,000 "invisible" alcohol calories per week.
Factors That Affect How Alcohol Hits You
Body weight, sex, food intake, hydration, and tolerance all affect blood alcohol concentration (BAC) from the same number of units. Women generally reach higher BAC than men at the same unit intake due to lower average body water percentage. Drinking on an empty stomach speeds alcohol absorption significantly. Standard drink sizes at home versus bars vary widely — home pours of wine and spirits frequently exceed "standard" serving sizes by 30–50%, making unit tracking at home less accurate without measuring.
How to Calculate Alcohol Units by Hand: Worked Example
Units = (volume in ml × %ABV) ÷ 1,000. Take a 500ml can of beer at 5% ABV: (500 × 5) ÷ 1,000 = 2.5 units. A 175ml glass of wine at 13% ABV: (175 × 13) ÷ 1,000 = 2.275 units, commonly rounded to 2.3. A 25ml spirit measure at 40% ABV: (25 × 40) ÷ 1,000 = 1 unit exactly — the reference point the entire unit system is built around.
How quickly do units add up across a typical evening?
Three 500ml beers at 5% ABV total 3 × 2.5 = 7.5 units in one evening — already more than half of a commonly cited 14-unit weekly guideline consumed in a single sitting. A bottle of wine (750ml at 13% ABV) contains (750×13)÷1,000 = 9.75 units, meaning one shared bottle between two people is roughly 4.9 units each, and a full bottle consumed alone approaches the entire weekly guideline in one evening.
Why Do Units Matter More Than Number of Drinks?
Why can two "one drink" servings contain very different amounts of alcohol?
A standard pour size assumption breaks down the moment ABV or serving size varies — a strong craft beer at 8% ABV in a 500ml can contains (500×8)÷1,000 = 4 units, considerably more than a standard 5% beer's 2.5 units, despite both being casually described as "one beer." Counting units rather than counting drinks is the only way to track total alcohol intake accurately when serving strengths vary this much.
Does alcohol contribute meaningfully to daily calorie intake?
Yes, and it's frequently underestimated. Pure alcohol provides roughly 7 calories per gram — nearly as much as fat (9 cal/g) and considerably more than protein or carbs (4 cal/g each) — and unlike food calories, alcohol calories are essentially "empty," providing no nutritional value. Three 2.5-unit beers in an evening contribute roughly 450–600 calories from the alcohol alone, before counting any mixers or the food commonly consumed alongside drinking.
What factors change how strongly the same number of units affects a person?
Body weight, sex, food intake before drinking, and individual metabolism all affect blood alcohol concentration independently of the raw unit count — the same 7.5 units consumed by two different people, or by the same person on an empty stomach versus after a full meal, can produce meaningfully different levels of impairment. Units measure alcohol consumed, not the physiological effect experienced, which is why unit counts are a consistent way to track intake but not a precise predictor of impairment for any single occasion.
Frequently Asked Questions
A standard pint (568ml) of 4% beer contains 2.3 units. A stronger 5% pint contains 2.8 units. Formula: Units = (Volume ml × ABV%) ÷ 1000.
The NHS recommends no more than 14 units per week for both men and women, spread over 3 or more days. 14 units is roughly equivalent to 6 pints of average-strength beer or 10 small glasses of wine.
Alcohol contains 7 calories per gram of pure alcohol (nearly as much as fat at 9 cal/g). A pint of beer is around 180–230 calories, a glass of wine 120–160 calories, a single spirit about 55–65 calories.
A standard 750ml bottle of 13% ABV wine contains 9.75 units — using the formula (750 × 13) ÷ 1,000. Shared between two people, that's roughly 4.9 units each; consumed alone in one sitting, it's close to the entire 14-unit weekly guideline.
No. Tolerance changes how drunk you feel at a given unit count, but it doesn't reduce the long-term health risks — liver damage, cancer risk, and cardiovascular effects are driven by total alcohol consumed over time, not by how affected you feel in the moment.
Sources & Methodology
Calculations are based on the most current publicly available data from authoritative government and industry sources: