Blood alcohol calculator
Estimate your blood alcohol concentration with the Widmark formula.
Only an estimate based on Widmark. Individual factors are not taken into account. Not a basis for deciding whether you are fit to drive – when in doubt, do not drive. Does not replace medical or legal advice, no guarantee given.
Legal blood alcohol limits in Germany
| Limit | Meaning |
|---|---|
| 0.0 ‰ | Novice drivers (probation) and under 21 |
| 0.3 ‰ | Relative incapacity to drive with signs of impairment |
| 0.5 ‰ | Fine, points, driving ban |
| 1.1 ‰ | Absolute incapacity to drive – criminal offence |
How the Widmark formula works
Blood alcohol is calculated from the pure alcohol consumed (amount × ABV × 0.8 g/ml), body weight and the reduction factor (men 0.7, women 0.6). Around 0.15 ‰ is broken down per hour. Individual factors such as a full stomach, daily condition or medication are not taken into account.
Frequently asked questions
How fast does the body break down alcohol?
On average around 0.1 to 0.15 per mille per hour – regardless of coffee, water or exercise.
How much alcohol do I have after 2 beers?
For an 80 kg man, roughly 0.5 to 0.6 per mille right after drinking – depending on build and time.
When can I drive again?
In Germany 0.5 per mille is the fine threshold; from 1.1 per mille it is a criminal offence. For novice drivers and under 21 the limit is 0.0 per mille.
Is this calculator legally binding?
No. It only gives a rough Widmark estimate and does not replace a measurement. When in doubt, do not drive.
Why does the value differ between men and women?
The reduction factor (body water content) is lower in women, so the value rises faster for the same amount.
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