How long until my BAC is zero?
The short answer: your body clears roughly 0.015% BAC per hour — about one standard drink an hour. Nothing speeds that up. Here's how to estimate your own sober-up time.
Sober-up time calculator
Estimate based on the average elimination rate of 0.015% BAC per hour. Individual rates vary from about 0.010% to 0.025%. This is not a fitness-to-drive test.
How your body processes alcohol
Your liver does about 90% of the work of breaking down alcohol, and it works at a fixed pace — roughly one standard drink (10 g of alcohol) per hour. That translates to your blood alcohol content falling by around 0.015% each hour, though the true rate varies between individuals depending on liver health, genetics, sex and body composition.
The crucial point: the liver has no fast-forward button. If you drink faster than one standard drink an hour, alcohol queues up in your bloodstream and your BAC rises. Once you stop drinking, the only thing that lowers it is time.
Typical sober-up times
| Current BAC | Time until under 0.05 | Time until 0.00 |
|---|---|---|
| 0.05 | — | ~3.5 hours |
| 0.08 | ~2 hours | ~5.5 hours |
| 0.10 | ~3.5 hours | ~7 hours |
| 0.15 | ~7 hours | ~10 hours |
| 0.20 | ~10 hours | ~13.5 hours |
These are averages. Your actual rate could be slower — which is why any estimate should be treated as a rough guide, never a green light.
Things that don't lower your BAC
- Coffee — caffeine makes you feel more alert. Your BAC doesn't move. An alert drunk person is still a drunk person.
- Cold showers — you'll be wide awake and exactly as intoxicated as before.
- Eating — food before or while drinking slows alcohol absorption, but once alcohol is in your blood, eating won't remove it faster.
- Vomiting — only removes alcohol still in your stomach; anything absorbed is staying for the duration.
- Exercise or sweating — only about 10% of alcohol leaves via breath, sweat and urine. Sweating it out is a myth.
How the estimate works: the Widmark formula
Most BAC calculators — including the one built into the Drink Buddy app — use the Widmark formula, the same method used in medical research and forensic contexts. It estimates peak BAC from the grams of alcohol consumed, your body weight and a distribution factor based on sex, then subtracts the elimination rate multiplied by hours elapsed.
Time to zero is then simply your current BAC divided by your elimination rate. At the average rate, a BAC of 0.09 takes about six hours to clear.
Frequently asked questions
How fast does BAC go down?
About 0.015% per hour on average — roughly one standard drink per hour. Individual rates range from around 0.010% to 0.025% per hour.
Does coffee, food or a cold shower sober you up faster?
No. Your liver metabolises alcohol at a fixed rate. Only time lowers BAC.
Can I still be over 0.05 the morning after?
Absolutely. After a big night, plan on not driving the next morning at all.
How accurate are BAC calculators?
They're estimates. Metabolism, food, medication and health conditions all shift your actual BAC. Use them for awareness, never to decide whether you can drive.