- What is a UK alcohol unit?
- A UK alcohol unit is 8 grams of pure alcohol, equivalent to 10 mL of pure ethanol. The UK adopted this small unit precisely so the maths is easy: a 25 mL single shot of 40% spirits contains 10 mL of pure alcohol — exactly one unit. The formula is (volume in mL × ABV%) ÷ 1000. A pint of 5% beer is (568 × 5) ÷ 1000 = 2.84 units. A 175 mL glass of 12% wine is (175 × 12) ÷ 1000 = 2.1 units.
- What is a US standard drink?
- A US standard drink is 14 grams of pure alcohol, equivalent to 0.6 fl oz of pure ethanol. That's the NIAAA (National Institute on Alcohol Abuse and Alcoholism) definition. By design, three classic American servings each contain about one standard drink: a 12 fl oz beer at 5%, a 5 fl oz glass of wine at 12%, and a 1.5 fl oz shot of 80-proof spirits (40%). The formula is (volume in fl oz × ABV ÷ 100) ÷ 0.6.
- Why does the UK count alcohol differently from the US?
- Two different public-health traditions. The UK adopted the alcohol unit in the 1980s as a small, easy-to-compute number — small enough that even a single shot or half-pint is a whole-number multiple. The US went with a larger standard drink calibrated to typical American serving sizes — a 12 oz beer, a 5 oz wine pour, a 1.5 oz shot. Both are measuring the same thing (grams of pure ethanol), just at different denominations. 1 US standard drink = 1.75 UK units.
- What's the UK weekly drinking guideline?
- The UK Chief Medical Officers' Low Risk Drinking Guidelines (updated 2016, reviewed 2023) recommend no more than 14 units per week for both men and women, spread over at least three days with several alcohol-free days. Above 14 units per week is officially the 'increasing risk' band; above 35 units per week for women or 50 for men is the 'higher risk' band. The 2016 update was significant — before then men had a higher allowance (21 units), and the change was based on cancer and cardiovascular evidence.
- What's the US drinking guideline?
- The US Dietary Guidelines for Americans (2020-2025) recommend that adults of legal drinking age can choose not to drink — and if they do drink, they should limit intake to 1 standard drink per day for women and 2 standard drinks per day for men. The guidelines explicitly add that drinking less is better for health than drinking more, and that some people should not drink at all (pregnancy, certain medical conditions, certain medications, recovery from alcohol use disorder, anyone under 21).
- Is there really a safe level of drinking?
- Modern public-health bodies — including the World Health Organization (WHO) in its 2023 statement and Canada's 2023 guidance — increasingly say no level of alcohol is risk-free, and that risk rises continuously with intake. The UK 14-units and US 1-2 drinks/day numbers are 'low-risk' thresholds, not 'safe' thresholds. Cancer risk in particular rises from very low levels of intake (alcohol is a Group 1 carcinogen — same category as tobacco and asbestos). The guidelines exist because zero is impractical to recommend; they're a harm-reduction frame, not a permission slip.
- Why does ABV matter so much?
- Because the same volume of drink can deliver wildly different amounts of pure alcohol. A pint of 4% lager is 2.27 UK units; a pint of 8% craft IPA is 4.55 — twice as much. A 175 mL glass of 11% wine is 1.93 units; the same glass of 14% wine is 2.45. Strong wines and craft beers are easy to under-count if you assume the typical 5% beer or 12% wine. Look at the bottle label or pump clip — ABV must be displayed by law.
- What's the difference between a UK shot, a US shot, and a 'shot'?
- A UK pub single is 25 mL by law (35 mL in some pubs); the typical American shot is closer to 44 mL (1.5 fl oz, the NIAAA standard drink reference). A 'shot' on a cocktail recipe with no country context is ambiguous — it could be either. The calculator uses 25 mL for the preset because that's the UK pub standard and also the volume that makes the maths land on exactly 1 UK unit for 40% spirits.
- How accurate is the formula?
- Both formulas are exact by definition — the UK alcohol unit and the US standard drink are defined by mass of pure ethanol, and the ABV percentage and volume are what go on the label. The only small inaccuracy is the conversion from volume to mass (1 mL of pure ethanol = 0.789 g, so 10 mL = 7.89 g ≈ 8 g), which gives the UK unit its 'about 8 grams' rounding. The numbers this tool produces are the same numbers the NHS, NIAAA, and UK government calculators produce for the same inputs.
- Is my data stored?
- No. Everything you type runs in your browser and disappears when you close the tab. We never send your drinking data, your weekly habits, or anything else to a server. We never log it, never store it, never share it.
