🍷 Alcohol Units, BAC Clearance & Calories Calculator
Calculate standard alcohol units, pure ethanol grams, drink calories, and estimated biological body clearance hours from beverage volume and ABV %.
What Alcohol Units, BAC Clearance & Calories Calculator Does
This calculator takes a drink's volume and strength and returns the pure alcohol it contains in grams, expressed both as UK units and as US standard drinks, along with the energy it carries.
The two measures exist because two countries settled on different reference amounts for the same underlying quantity. A UK unit is 8 grams of ethanol; a US standard drink is 14 grams. Neither is more correct, but they are not interchangeable, and a figure quoted in one is meaningless against a guideline written in the other — a 1.75-fold difference is not a rounding error.
The calorie figure is split deliberately. Ethanol carries 7 kcal per gram and that part is exact arithmetic. Carbohydrate carries 4 kcal per gram and varies enormously between drinks — near zero in distilled spirits, substantial in beer and sweet wines. This tool used to apply a flat 35% uplift to every drink to cover "residual carbs", which inflated a shot of vodka by a third for sugar it does not contain. Carbohydrate is now an input.
How to Use Alcohol Units, BAC Clearance & Calories Calculator
- Select a drink preset or enter drink volume (ml) and ABV percentage
- Review calculated standard alcohol units and pure alcohol grams
- Inspect estimated beverage calories and hepatic clearance time in hours
Formula Used by Alcohol Units, BAC Clearance & Calories Calculator
Pure alcohol in a drink
grams of ethanol = volume (ml) × (ABV ÷ 100) × 0.789
- ABV
- Alcohol by volume, the percentage on the label
- 0.789
- Density of ethanol in g/ml at room temperature — this is what converts a volume of alcohol into a mass
Worked example
The three drinks NIAAA uses to define a US standard drink.
- 12 fl oz beer at 5%: 354.9 ml × 0.05 × 0.789 = 14.00 g
- 5 fl oz wine at 12%: 147.9 ml × 0.12 × 0.789 = 14.00 g
- 1.5 fl oz spirits at 40%: 44.4 ml × 0.40 × 0.789 = 14.00 g
Result: Exactly 14.00 grams in all three — which is the definition reproducing itself, and a useful check that the formula here matches the federal one. NIAAA gives the same quantity as 0.6 fluid ounces of pure alcohol, which is also 14.00 g.
UK units and US standard drinks
UK units = volume (ml) × ABV ÷ 1,000; US standard drinks = grams of ethanol ÷ 14
- UK unit
- 8 g of ethanol, or 10 ml of it
- US standard drink
- 14 g of ethanol, or 0.6 fl oz
Worked example
A 500 ml pint of 5% beer.
- UK units: 500 × 5 ÷ 1,000 = 2.50
- Ethanol: 500 × 0.05 × 0.789 = 19.73 g
- US standard drinks: 19.73 ÷ 14 = 1.41
Result: 2.50 UK units, or 1.41 US standard drinks. The ratio between the two scales is always 1.75, because 14 ÷ 8 = 1.75.
Where the calories come from
kcal = (grams of ethanol × 7) + (grams of carbohydrate × 4)
- 7
- kcal per gram of ethanol — more than carbohydrate or protein, less than fat
- 4
- kcal per gram of carbohydrate — residual sugars, and in beer the unfermented dextrins
Worked example
A 500 ml pint of 5% beer with about 13 g of carbohydrate, then a 44 ml shot of 40% spirits with none.
- Pint: (19.73 × 7) + (13 × 4) = 138 + 52 = 190 kcal
- Shot: (13.89 × 7) + (0 × 4) = 97 + 0 = 97 kcal
Result: 190 kcal and 97 kcal. Under the old flat 35% uplift the shot would have read 131 kcal — a third of it attributed to carbohydrate that is not present in distilled spirits at all.
The Two Scales, and the Presets on This Page
Ethanol mass is the common currency; both unit systems are derived from it. Carbohydrate figures are typical values, not label data.
| Drink | Ethanol | UK units | US standard drinks | Calories |
|---|---|---|---|---|
| Pint of beer, 500 ml at 5% | 19.73 g | 2.50 | 1.41 | 190 kcal |
| Glass of wine, 175 ml at 13% | 17.95 g | 2.27 | 1.28 | 142 kcal |
| Single shot, 44 ml at 40% | 13.89 g | 1.76 | 0.99 | 97 kcal |
| Pint of craft IPA, 568 ml at 6.8% | 30.47 g | 3.86 | 2.18 | 293 kcal |
One US Standard Drink, According to NIAAA
Each of these contains 14 g (0.6 fl oz) of pure alcohol. The serving sizes differ by a factor of eight because the strengths do.
| Beverage | Serving | Typical ABV |
|---|---|---|
| Regular beer | 12 fl oz | ~5% |
| Malt liquor or hard seltzer | 8–10 fl oz | ~7% |
| Table wine | 5 fl oz | ~12% |
| Fortified wine (sherry, port) | 3–4 fl oz | ~17% |
| Cordial, liqueur, aperitif | 2–3 fl oz | ~24% |
| Distilled spirits | 1.5 fl oz | ~40% |
The Same Guidelines, Converted to Grams of Ethanol
The only way to compare them. UK guidance is a weekly figure applying to everyone; US guidance is a daily limit that differs by sex. The weekly column annualizes the US daily limits for comparison only — it is not how the US guidance is written.
| Guideline | As published | Grams of ethanol per week | In the other system |
|---|---|---|---|
| UK Chief Medical Officers | 14 units per week | 112 g | 8.0 US standard drinks |
| US, men | Up to 2 drinks per day | 196 g | 24.5 UK units |
| US, women | Up to 1 drink per day | 98 g | 12.25 UK units |
How to Read Your Result
A "drink" is a measurement, not a serving
The NIAAA table is the useful thing to internalize: a 12-ounce beer, a 5-ounce wine and a 1.5-ounce shot are the same amount of alcohol. What is poured at home rarely matches. A generous glass of wine is easily 8 ounces rather than 5, and a craft beer at 6.8% in a 568 ml pint is 2.18 standard drinks — more than double the nominal one. Counting glasses systematically undercounts; counting grams does not.
The two countries' limits are further apart than they look
Converted to a common unit, the UK advises no more than 112 g of ethanol a week for anyone, while the US daily limit for men works out at 196 g across a week — 75% higher. The comparison is imperfect because the US figure is a daily cap rather than a weekly allowance, and daily caps are explicitly not meant to be averaged or saved up. But the gap is real, and it is a reminder that "within the guidelines" means something different depending on which country wrote them.
Alcohol calories are not the whole story, and they are not nothing
At 7 kcal per gram ethanol sits between carbohydrate and fat, and the pint above carries 138 kcal from alcohol before a single gram of carbohydrate is counted. It is also metabolized preferentially — the body deals with it ahead of other fuels — so it is not readily stored but it does displace the oxidation of what you ate alongside it. The practical point for anyone tracking intake is simply that drinks are usually the least-logged calories in a day.
This tool deliberately does not estimate sobriety
An earlier version reported an "estimated body clearance time" derived from an invented rate. That has been removed. Alcohol elimination varies with body composition, sex, liver function, food, medication and drinking history, and no calculator working from volume and ABV alone can produce a number that is safe to act on. Nothing here should be read as an indication of fitness to drive, and the legal threshold in any case is a blood or breath concentration, not an elapsed time.
Limitations & Accuracy Notes
- One drink at a time. There is no session or weekly total, and no running tally against a guideline.
- Carbohydrate is entered by you. The preset values are typical figures for the drink type, not label data — beers in particular range widely, and a sweet or high-gravity beer carries far more than a light one.
- No protein or residual fat, which are negligible in most drinks but not zero in some (cream liqueurs, for instance, are not modeled well by this at all).
- No blood alcohol concentration, no elimination rate and no sobriety estimate, deliberately — see above.
- Assumes ethanol density of 0.789 g/ml at room temperature. This shifts slightly with temperature and is immaterial at the precision anyone drinks at.
- Guideline figures are for healthy non-pregnant adults. They do not apply during pregnancy, where guidance in both countries is no alcohol, nor to anyone with a condition or medication that interacts with alcohol.
- Not medical advice. If the reason you are counting is that you are concerned about your drinking, the tools listed in the sources below lead to actual support.
Frequently Asked Questions
How are standard alcohol units calculated?
How fast does the human body process alcohol?
What is a unit of alcohol?
Is a UK unit the same as a US standard drink?
What are the low-risk drinking guidelines?
Where do the calories in alcohol come from?
How long does it take to be safe to drive?
Is my data stored?
References & Further Reading
- NIAAA — What Is A Standard Drink? — The US federal definition: one standard drink is 14 grams, or 0.6 fluid ounces, of pure alcohol. Source of the equivalent-servings table above
- NIAAA — Rethinking Drinking — NIH resource for checking drinking against US guidelines, with calculators and support information
- NHS — Calculating alcohol units — The UK definition of a unit as 8 g / 10 ml of pure alcohol, the ABV × volume ÷ 1,000 formula, and the 14-unit weekly guideline