TempoLife › Features › Alcohol units, calories and clearance

Alcohol: units, calories and clearance

Turn any drink into grams of pure ethanol, UK units, US standard drinks and Estonian/Finnish units, see where its calories come from, and read an estimate of how long the alcohol takes to clear — with the model's assumptions written out.

Never use this page to decide whether to drive. Clearance is an estimate from a simplified model and varies with your liver, your genetics, your medicines, food, sleep and illness — real elimination rates differ between people by a factor of two, and the model does not know which end you are at. The only safe level of alcohol for driving is none, and a legal limit is not a safety threshold. If you have been drinking, do not drive.

Work out any drink

Every drink, computed on the server

Source: USDA FoodData Central SR Legacy (public domain) — carbohydrate values · checked 2026-09-02

How the grams are worked out

ethanol (g) = volume (ml) × ABV% ÷ 100 × 0.789

UK unit          = 10 ml pure ethanol ≈ 8 g
US standard drink= 14 g
EE / FI unit     = 12 g

kcal = ethanol g × 7 + carbohydrate g × 4

0.789 is the density of ethanol in grams per millilitre at 20 °C, and 7 kcal per gram is the standard Atwater factor for alcohol. Both the volume and the ABV are printed on the container by law, so for a single drink this is not an estimate at all — it is multiplication. Everything uncertain on this page is downstream of it.

The three unit definitions are the reason this site works in grams. A 175 ml glass of 13% wine is 2.4 UK units, 1.3 US standard drinks and 1.5 Estonian or Finnish units. Those are three different numbers for one identical glass, and comparing a guideline written in one system against a drink counted in another is how people end up wrong by fifty per cent without making an arithmetic mistake.

The Widmark equation, and what it does not know

Every clearance figure on this site comes from the Widmark equation, published in the 1930s and still the basis of most forensic and public-information estimates:

BAC (‰, g/L) = A ÷ (r × m)  −  β × t

A = grams of pure ethanol
m = body mass in kg
r = distribution factor: about 0.68 (men), 0.55 (women)
β = elimination rate, about 0.15 ‰ per hour
t = hours since drinking

The distribution factor exists because ethanol dissolves in body water, not in fat. A body with a higher proportion of water spreads the same dose through a larger volume and reaches a lower concentration, which is most of the reason the male and female factors differ — it is body composition, not sex as such.

Now the assumptions, in full, because a number without them is worse than no number:

• Absorption is instant. The model puts the whole dose in the bloodstream at once. Real absorption takes 30 to 90 minutes and depends on food, carbonation and how fast you drank.
• Elimination is linear and identical for everyone. It is neither. Published rates range from roughly 0.10 to 0.20 ‰ an hour between individuals, and heavy regular drinkers clear faster than occasional ones.
• The distribution factor is a population average. Body composition moves it, and two people of the same weight and sex can differ meaningfully.
• It knows nothing about you. Not your liver, your medicines, your illness, your sleep, your age, or whether you ate.
• It models one dose. Drinking across an evening is a series of overlapping doses, and the real curve stays high far longer than a single-dose model suggests.

Put together, that is why the output on this page is described as an estimate every single time it appears, and why it must never be used as a driving decision.

Source: Widmark equation — the standard forensic and public-information model for blood alcohol estimation · checked 2026-09-02

Never use this page to decide whether to drive. Clearance is an estimate from a simplified model and varies with your liver, your genetics, your medicines, food, sleep and illness — real elimination rates differ between people by a factor of two, and the model does not know which end you are at. The only safe level of alcohol for driving is none, and a legal limit is not a safety threshold. If you have been drinking, do not drive.

Weekly totals

National low-risk drinking guidelines are not the same figure in different countries, they are written in different unit sizes, and several have been revised downward in recent years. The one people quote most often is the UK Chief Medical Officers' guideline of 14 units a week for both men and women, which is 112 g of ethanol. The table below simply converts weekly ethanol totals into drinks, so you can apply whichever guideline actually applies where you live.

Source: UK Chief Medical Officers' low risk drinking guidelines (14 units a week) — cited as the named example; check the guideline in your own country · checked 2026-09-02

One page per drink

Frequently asked questions

Exercise library · Daily calorie needs · Calorie needs by life stage · Common questions