When can I drive after drinking?

Written byOleh Soloninupdated 27 September 2026

Sex

Weight (kg)

Hours since the first drink

Drinks

Drink 1

Volume (ml)

Drink strength (%)

BAC estimate

This is a formula estimate, not a measurement. If you have been drinking, do not drive.

Pure alcohol consumed: 19.7 g
Peak estimate: 0.36 ‰
Current estimate: 0.06 ‰
Breath alcohol now, roughly: 0.026–0.031 mg/L
Estimated time to 0.0: 0.4 h

Time to 0.0 is a rough guide at an average elimination rate of 0.15‰ an hour. The formula is least reliable in the first hour after drinking and after food.

Breath is converted from blood as a range: countries' laws divide blood concentration by factors between 2000 and 2400.

The Russian limit

Under the note to Article 12.8 of the Russian Code of Administrative Offences, a driver is intoxicated above 0.16 mg/L of exhaled air or from 0.3 g/L of blood. Limits elsewhere differ. The estimate cannot tell you which side of any limit you are on.

What the Widmark formula suggests, and why it cannot be trusted to the decimal

Estimate blood alcohol concentration from drinks, body weight and time elapsed using the Widmark formula. An estimate only — never a driving decision.

This applies the Widmark equation: alcohol consumed, divided by body weight and a distribution factor, minus what your liver has processed since the first drink.

Treat the number as an order of magnitude, not a measurement. Real BAC depends on food, sex, medication, liver function, hydration and drinking speed — so two people with identical inputs can end up with noticeably different readings.

How to use

Enter your sex and body weight — they set how much body water the alcohol spreads through.
Add everything you drank: pick a ready-made serving of beer, wine or spirits, or type your own volume and strength.
Enter the hours since the first drink and read the peak, the current estimate, a rough breath figure and the time to 0.0.

How long alcohol takes to clear

Time to zero is the peak level divided by an average elimination rate of 0.15‰ an hour. The table gives the order of magnitude for a man of 80 kg and a woman of 60 kg drinking one serving at once. For any one person the rate can be noticeably slower or faster.

A US standard drink holds 14 grams of alcohol — a 355 ml beer at 5 percent or a 44 ml shot of 40 percent spirit — and both land at the same estimated peak.

Every row comes from the calculator on this page; the percentage is the per-mille figure divided by ten. An estimate from a formula, not a time after which it is safe to drive.
Drink	Alcohol, g	Man 80 kg: peak	To 0.0	Woman 60 kg: peak	To 0.0
Beer 355 ml, 5%	14	0.26‰ (0.026%)	1.7 h	0.42‰ (0.042%)	2.8 h
Pint of beer 568 ml, 4%	17.9	0.33‰ (0.033%)	2.2 h	0.54‰ (0.054%)	3.6 h
Two pints, 4%	35.9	0.66‰ (0.066%)	4.4 h	1.09‰ (0.109%)	7.2 h
Wine 175 ml, 12%	16.6	0.30‰ (0.030%)	2 h	0.50‰ (0.050%)	3.3 h
Wine 250 ml, 13%	25.6	0.47‰ (0.047%)	3.1 h	0.78‰ (0.078%)	5.2 h
Bottle of wine 750 ml, 12%	71	1.31‰ (0.131%)	8.7 h	2.15‰ (0.215%)	14.3 h
Spirit shot 44 ml, 40%	13.9	0.26‰ (0.026%)	1.7 h	0.42‰ (0.042%)	2.8 h

Where the Widmark formula goes wrong

The formula assumes all alcohol is absorbed at once, so it overstates the level in the first hour after drinking, and after food it overstates both the peak and the time to zero. Even in its best case — one drink on an empty stomach, a few hours later — the result stays an estimate, not a measurement: the error depends on the person and on the inputs.

Breath and blood are linked only approximately: countries' laws convert between them with factors from 2000 to 2400, which is why the breath figure is shown as a range. Two pints for an 80 kg man estimate 0.66‰ at the peak, which the calculator shows as 0.275–0.33 mg per litre of breath.

What this calculator shows

Estimated grams of alcohol consumed
Approximate peak and current BAC
A rough time until alcohol would clear at an average elimination rate

What to keep in mind

Elimination is assumed at roughly 0.15‰ per hour, which varies substantially between individuals.
This is not a legal or medical instrument. If you have been drinking, do not drive — no calculator can tell you that you are safe.

Where the numbers come from

Checked against the Widmark formula; the note to Article 12.8 of the Russian Code of Administrative Offences · verified September 2026.

FAQs

Can I use this to decide whether to drive?

No. It is an estimate with wide error bars, and the only safe rule after drinking is not to drive. Police tests measure you, not an average person.

What is the drink-drive limit?

It depends on where you are: 0.08 percent in most of the US, 80 mg per 100 ml of blood (0.8‰) in England and Wales, 50 mg (0.5‰) in Scotland and much of Europe. Being under a limit on a calculator proves nothing — the test measures you.

How long does it take to sober up from two pints?

For an 80 kg man the formula estimates about 4.4 hours to zero; for a 60 kg woman, about 7.2. Individual elimination rates vary widely around the 0.15‰ an hour average used here.

Does coffee or a cold shower speed things up?

Neither. The liver processes alcohol at its own pace. Caffeine can make you feel more alert while leaving you just as impaired, which is arguably more dangerous.

Why do men and women get different results?

Body water differs on average, so the same alcohol reaches a higher concentration. The formula uses a distribution factor of 0.68 for men and 0.55 for women, but individual variation is still large.

Does eating first change the outcome?

Food slows absorption, so the peak is lower and later. It does not reduce the total amount your body must process.

Worked example

Half a litre of beer

Input: 500 ml at 5%, a man of 80 kg, two hours elapsed

Output: A peak of about 0.36‰, about 0.06‰ two hours later

Note: The formula promises almost nothing left, but it does not know how fast your own body clears alcohol. A roadside test measures you, not an average person.

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When can I drive after drinking?

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