Alcohol Units Calculator: Wine, Vodka and Spirits

One UK alcohol unit equals 10 millilitres (or 8 grams) of pure ethanol. This is not the same as one drink — it is a standardised measure of the actual alcohol content inside a drink. A single unit is roughly the amount your liver can process in one hour, although this varies significantly by body weight, sex, age, and individual metabolism.

The unit system exists to give people a consistent way to compare alcohol intake across different drink types and serving sizes. A 25 ml shot of 40% ABV vodka contains exactly 1 unit. A 250 ml glass of 13% wine contains 3.25 units. A pint of 4% lager contains 2.3 units. Without the unit framework, comparing these across such different volumes and strengths would be impractical.

How units differ from standard drinks internationally

• UK unit: 10 ml / 8 g of pure ethanol — the basis for NHS guidelines.
• Australian standard drink: 10 g of ethanol — nearly identical to the UK unit.
• US standard drink: 14 g of ethanol — approximately 1.75 UK units, significantly larger.
• WHO standard drink: 10 g of ethanol — aligns with UK and Australian definitions.

The alcohol units formula is straightforward and works for every type of drink. You need two pieces of information: the volume of the drink in millilitres and the ABV (Alcohol By Volume) percentage printed on the label or menu.

The formula

Units = (Volume in ml × ABV%) ÷ 1,000. For a 330 ml bottle of beer at 5% ABV: `(330 × 5) ÷ 1,000 = 1.65 units`. For a 700 ml bottle of whisky at 40% ABV: `(700 × 40) ÷ 1,000 = 28 units`. The formula works for any drink, any serving size, and any ABV percentage — it just requires the correct inputs.

Why ABV is the critical variable

ABV varies widely within the same drink category. Wine ranges from 9% (light Italian whites) to 15% (full-bodied Californian reds). Beer ranges from 2.5% (session ales) to 12%+ (barleywines and strong ales). A 250 ml glass of 9% wine contains 2.25 units; the same glass of 15% wine contains 3.75 units — a 66% difference from the same serving size. Always check the ABV on your specific bottle rather than using a category average.

The Alcohol Unit Calculator removes the need to do this arithmetic manually. Enter the volume and ABV and the unit count is instant. You can run multiple entries in sequence to build up a total for an evening or a week.

Wine, beer, and cider are the three most commonly consumed alcoholic drinks in the UK, and they are also the three categories where serving size and ABV vary most widely — which is where unit miscalculation most often occurs.

Wine

Wine ABV typically ranges from 9% to 15%. A small glass (125 ml) at 12% ABV is 1.5 units. A medium glass (175 ml) at 12% is 2.1 units. A large glass (250 ml) at 13% is 3.25 units. A standard 750 ml bottle at 13% ABV contains 9.75 units — just over the two-thirds of the 14-unit weekly limit in a single bottle. Prosecco and champagne are typically 11–12% ABV; dessert wines and port run from 17% to 20%.

Beer and lager

Standard lager at 4% ABV: a 330 ml can = 1.32 units; a 568 ml pint = 2.27 units. A 440 ml can of 5% craft lager = 2.2 units. A pint of 6% IPA = 3.4 units — more than a medium glass of wine. Session ales (3.5–4%) keep units lower per pint; premium lagers and craft beers (5–7%) accumulate units quickly across a session.

Cider

Mainstream ciders (4–4.5% ABV) contain similar units to standard lager: a pint of 4.5% cider = 2.56 units. Premium and craft ciders run 6–8% ABV — a pint of 7% cider is 3.97 units, almost as much as a large glass of wine. Draught cider at a pub is often served in pints even when it is strong, making it easy to consume more units than expected.

Spirits are high-ABV drinks consumed in small volumes, which makes accurate unit calculation especially important — the difference between a single and a generous pour is the difference between 1 unit and 2 units. Pub measures in the UK are standardised; home pours typically are not.

Single and double measures

UK pub single spirit measure: 25 ml at 40% ABV = 1 unit exactly. A double (50 ml at 40%) = 2 units. A large measure (35 ml, common in Scotland and Ireland at 40% ABV) = 1.4 units. Premium spirits vary: a 25 ml measure of 57% Navy Strength rum = 1.43 units; a 25 ml measure of 50% ABV tequila = 1.25 units. Always check the ABV label — "overproof" spirits and premium whiskies often exceed 40%.

Common spirits by the bottle

• Vodka (700 ml, 40% ABV): 28 units per bottle. A standard mixer drink (50 ml vodka) = 2 units.
• Gin (700 ml, 37.5–47% ABV): 26.25 to 32.9 units per bottle depending on ABV.
• Whisky/Scotch (700 ml, 40%): 28 units per bottle. A dram (35 ml) = 1.4 units.
• Brandy/Cognac (700 ml, 40%): 28 units per bottle. A pub brandy (25 ml) = 1 unit.
• Rum (700 ml, 40%): 28 units per bottle. Dark rum is often 43–50% — check the label.
• Tequila (700 ml, 38–50%): 26.6 to 35 units per bottle. Mezcal often runs 45–55%.

The safest approach is not to drink regularly more than 14 units per week, to keep your risk of illness and accidents low.

Cocktails and mixed drinks

Cocktails are the hardest category to estimate without knowing the recipe. A standard Gin and Tonic (50 ml gin at 40%) = 2 units. A Mojito with a double rum measure = 2 units from the rum alone. A Long Island Iced Tea with five spirit measures (5 × 25 ml at 40%) = 5 units in a single glass. Use the Alcohol Unit Calculator to calculate each spirit ingredient separately and sum the results for a complete cocktail unit count.

The UK Chief Medical Officers recommend that adults drink no more than 14 units per week as a low-risk guideline. This applies equally to men and women — the previous guideline (21 units for men, 14 for women) was revised in 2016 based on updated evidence on cancer risk. The 14-unit limit is not a safe threshold; it is the level at which health risks are considered low.

What 14 units looks like in practice

• 6 pints of average-strength (4%) lager (6 × 2.3 = 13.8 units).
• 10 small glasses (125 ml) of low-strength (12%) wine (10 × 1.5 = 15 units — slightly over).
• 14 single measures (25 ml at 40%) of spirits.
• One and a half 750 ml bottles of 13% wine (9.75 × 1.5 = 14.6 units).

The NHS also recommends spreading those units across at least three separate days — not saving them for a single weekly session. Binge drinking (consuming 6+ units for women, 8+ for men in a single session) significantly increases the risk of acute alcohol-related harm regardless of the weekly total.

Alcohol and calories

Alcohol provides 7 calories per gram — more than carbohydrates or protein. One unit (8 g of ethanol) contains approximately 56 calories from alcohol alone, before mixers, sugars, or carbohydrates in beer. A large glass of 13% wine (3.25 units) is around 228 calories from alcohol plus additional calories from sugars in the wine. Use the Calorie Burn Calculator to understand how physical activity offsets alcohol calories.

Understanding how your body processes alcohol puts the unit calculation in context. The rate of absorption, the effect on BAC (Blood Alcohol Concentration), and the time needed to clear alcohol from your system all depend on the same inputs that drive the unit formula.

Processing rate

The liver processes roughly 1 unit of alcohol per hour for an average adult. This rate varies with body weight, sex, liver health, and genetics — it is not possible to speed it up through coffee, water, food, or exercise. Consuming more than 1 unit per hour causes BAC to rise. The BAC Calculator estimates your blood alcohol concentration based on units consumed, body weight, and time elapsed since your first drink.

Factors that affect intoxication

• Body weight: A higher body weight means more body water to dilute alcohol — a lighter person reaches a higher BAC from the same units.
• Biological sex: Women generally have lower body water percentage and less alcohol dehydrogenase enzyme activity, resulting in higher BAC per unit.
• Food intake: Eating before or while drinking slows alcohol absorption significantly, flattening the BAC curve.
• Medication: Many medications interact with alcohol — statins, antihistamines, antibiotics, and antidepressants can all intensify effects.
• Tolerance: Regular drinkers develop metabolic and neurological tolerance — they feel less intoxicated at a given BAC, but the organ-level effects remain.

Knowing the unit formula is one thing; actually tracking units consistently requires a practical system. These approaches work across different contexts — pub visits, home drinking, and social occasions where quantities are less predictable.

At a pub or bar

UK licensed venues are legally required to display unit counts on menus and at the point of sale for major drink categories. If the ABV is displayed, apply the formula mentally for your specific serving size. A quick mental check: a pint of 4% beer ≈ 2.3 units, a large wine ≈ 3 units, a single spirit ≈ 1 unit. Keep a running total using the calculator before ordering another round.

At home

Home pours are consistently larger than pub measures, which is where unit tracking most often breaks down. A 250 ml "glass" of wine at home — often poured to the brim of a large glass — may be closer to 300 ml: `(300 × 13) ÷ 1,000 = 3.9 units` rather than the assumed 3.25. Use a measure or scale occasionally to calibrate your pours. The Alcohol Unit Calculator handles any custom volume you enter.

Building a weekly picture

The 14-unit weekly limit is most useful when tracked cumulatively across the week, not evaluated drink by drink. Keep a simple tally — a note in your phone or a quick entry in the calculator after each drinking occasion. Spread units across three or more days. If you exceeded the guideline one week, the most evidence-based response is to have more alcohol-free days the following week rather than abstaining entirely.