Work out a rough estimate of how long it takes for your blood alcohol content to reach zero, based on an average elimination rate.
Sober at approximately
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Hours until sober
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Elimination rate
0.15 ‰/hour
Never drive based on this result. This is only a very rough average estimate. Individual differences in metabolism, stomach contents, sleep and health can mean your actual blood alcohol content is higher — and takes longer to clear — than the calculation shows. Never judge your own ability to drive based on this calculator alone.
Enter your estimated blood alcohol content right now, for example from a breathalyzer or blood alcohol calculator.
The calculator works out how many hours it takes for your blood alcohol content to reach 0.0‰ at an average elimination rate.
See the estimated time you'd be back to zero — but remember this is only a rough estimate.
How the time to sober up is calculated
The body breaks down alcohol at a relatively steady pace, regardless of how much you've had to drink. The calculator uses a commonly cited average value of 0.15 per mille per hour:
Hours until sober = BAC now ÷ 0.15
With a blood alcohol content of 0.8‰, this calculation gives roughly 0.8 ÷ 0.15 ≈ 5.3 hours until it reaches zero. In practice, this figure varies from person to person and can be affected by body weight, sex, food in the stomach, medication and general health.
Important: This is only a rough mathematical average estimate. Even if the calculator shows your blood alcohol content "should" be zero, your actual level may still be measurable — and you may still be impaired. The only safe option is not to drive after drinking alcohol, and to wait well beyond the calculated time, or use a breathalyzer before driving. Legal blood alcohol limits for driving vary by country and jurisdiction — check the rules that apply where you are.
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Frequently asked questions
Can I trust that I'm sober when the calculator says so?
No. This is only a rough mathematical average estimate. Individual variation is large, and the actual elimination rate can be both faster and slower than 0.15‰/hour. Never use this calculator to decide whether it's safe to drive.
Why is 0.15 per mille per hour used?
0.15‰/hour is a widely used average value for how quickly the body breaks down alcohol. The actual elimination rate normally varies between about 0.10 and 0.20‰/hour depending on the person.
Does coffee, a shower or food help you sober up faster?
No. Neither coffee, a cold shower, fresh air nor food speeds up how fast alcohol is broken down. Only time brings blood alcohol content down.
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