One beer (350 mL, 5%), 75 kg
- Input
- 1 dose
- Expected output
- ≈ 1h48 até zero
Estimated initial BAC of about 0.27 g/L, already above zero, so already an administrative infraction if driving.
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how long does alcohol stay in your blood
Unlike food, the body cannot "absorb faster" to speed up alcohol elimination: the liver processes it at a relatively constant rate, typically between 0.010 and 0.020 g/dL per hour. This page opens the calculator with a 75 kg male profile already filled in; add the example below (two 350 mL, 5% beers an hour apart) to reproduce the decay curve back down to zero.
Estimated initial BAC of about 0.27 g/L, already above zero, so already an administrative infraction if driving.
The time to zero does not simply double with the number of doses, because the first dose had already been decaying for an hour by the time the second one started.
Classic Widmark uses a fixed distribution factor (r), 0.68 for men and 0.55 for women, a population average. The Watson/Forrest method computes an individualized factor from your estimated total body water, based on height and weight, divided by weight, which tends to be closer to reality for people whose body composition falls outside Widmark's average, for example in cases of obesity.
No. Liver metabolism runs at the same rate whether you are asleep or awake, what changes is that you stop noticing the effects while asleep, which is exactly the danger: you may assume it has "worn off" on waking without your BAC actually being back to zero.
Do not use this number for that decision under any circumstance. It is an educational estimate with large individual variation, not a measurement, the only safe decision after drinking is not to drive.
This is an educational estimate, not a measurement of your real blood alcohol. Individual variation is large, and the tool does not know whether you ate, took medication, or have a different tolerance than average. In Brazil, the tolerance for the administrative infraction is zero from any detected alcohol concentration (CTB article 165). The only reliably correct decision after drinking is not to drive.
Watson/Forrest computes the distribution factor from your height and weight instead of using a fixed average per sex.
No drinks added yet. Add at least one to calculate BAC.
This number is not permission to drive. After drinking, do not drive, even with a low or zero result.
Add at least one drink to see the curve.
All the math runs in your browser. No profile or drink data is ever sent to a server.