Time to Sober Calculator

Track common drinks through an evening, estimate current BAC, see a live burndown toward zero, and check the rough sober-by time.

Session profile

Drinks consumed

Beer (355 ml / 12 oz, 5%)

Quick-add drink preset

0

Beer — strong (355 ml, 8%)

Quick-add drink preset

0

Wine (148 ml / 5 oz, 12%)

Quick-add drink preset

0

Wine — fortified (88 ml, 20%)

Quick-add drink preset

0

Shot / spirit (44 ml, 40%)

Quick-add drink preset

0

Cocktail (120 ml, 15%)

Quick-add drink preset

0
Do not use this to decide whether you can drive

This is a rough educational estimate only. Actual BAC depends on food intake, hydration, liver function, medications, and genetics.

Do NOT use this tool to decide whether you are safe to drive, operate machinery, or do any task that requires sobriety.

When in doubt, assume you are NOT sober. If you are concerned about your drinking, contact your GP or call Drinkline on 0300 123 1110 (UK).

Result

Enter values Add your body weight and at least one drink to estimate how long it will take to sober up.

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Alcohol

Time to sober calculator guide: rough BAC clearance timing, burndown estimates, and safety limits

A time to sober calculator estimates how long it may take for a logged drinking session to reach zero BAC if no more alcohol is consumed. It is useful for education and planning only. It is not accurate enough to decide whether you are fit to drive, work, supervise children, or do any activity that requires sobriety.

What this calculator does, and what it cannot do

The live tool keeps a session-based drink log, estimates current BAC from common drink presets, shows a burndown toward zero, and gives a rough sober-by clock time. The estimate updates as you add drinks or change the elapsed time since the first drink.

It cannot tell you when you are safe to drive. Actual alcohol absorption and elimination vary with food intake, hydration, body composition, liver function, medicines, genetics, sleep deprivation, and drinking pace. The estimate should be treated as a rough educational ceiling, not a safety clearance.

The formula behind the estimate

The calculation starts with the Widmark approach. Each drink is converted into grams of ethanol, then divided by body weight and a sex-specific body-water constant to estimate BAC before subtracting an average elimination rate for the hours since drinking started.

For the burndown view, the page assumes no more drinks are consumed from the current point onward and reduces the estimated BAC along a straight line using the same average elimination rate. That produces the remaining time, the sober-by clock time, and the checkpoint table shown on the result side.

Alcohol grams = volume x ABV x 0.789

Converts each drink into grams of pure ethanol using ethanol density in g/mL.

BAC (%) = alcohol grams / (weight in kg x r x 10) - (0.015 x hours elapsed)

Widmark-style estimate using sex-specific body-water constant r and an average elimination rate.

Worked example

Suppose an 80 kg man has one regular beer and checks the calculator immediately. The estimate lands near 0.024% BAC, with roughly 1 hour 36 minutes remaining to reach zero if he stops drinking there. Adding a second similar beer approximately doubles the estimated BAC and extends the time remaining.

That is why the session-tracker design matters. A person can keep adding drinks throughout an evening, watch the estimated sober-by time move later, and see how extra drinks stack on top of alcohol that has not yet cleared.

The safety message matters more than the number

Impairment starts well before zero BAC and often before legal driving thresholds. Even if a calculator shows a small number or a near-term sober-by time, that does not prove a person is safe to drive or operate machinery. When in doubt, assume you are not sober.

If you are concerned about your drinking, speak to your GP or use support services such as Drinkline. If someone is difficult to wake, vomiting repeatedly, having seizures, breathing slowly, or collapsing, treat that as an emergency rather than checking a calculator again.

Further reading

Frequently asked questions

Can coffee, food, or water sober me up faster?

No. Coffee may make you feel more awake, and water may help with thirst, but neither meaningfully speeds alcohol elimination. Time is the only reliable way for BAC to fall.

 Why does the calculator use time since the first drink?

The Widmark approach needs an elapsed-time assumption for alcohol already being absorbed and cleared during the session. Using time since the first drink is a practical simplification for a session tracker, even though real absorption is more complex than a single straight-line model.

 Why is my real breath-test result different from the estimate?

Because the calculator uses population averages. Food intake, stomach emptying, body-water distribution, liver metabolism, medications, genetics, and measurement timing can all move the real result above or below the estimate.

 What should I do if I am worried about my drinking?

Contact your GP or call Drinkline on 0300 123 1110 if you are in the UK. If there are emergency symptoms such as collapse, seizures, or slow breathing, call emergency services immediately.

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