BAC Sober Time Calculator
Estimate blood alcohol and how many hours until you are back to zero.
Enter your values
ⓘ Live results
Results
- Estimated BAC now
- 0.08%
- Status
- over the 0.05% limit
- Hours to 0.00%
- 5.3
- Hours to under 0.05%
- 2
- Peak BAC reached
- 0.11%
- Total alcohol
- 56 g
Working
- 1(56 g / (75 kg x 0.68)) x 100 = 0.11% peak
- 2minus 0.015 x 2 h = 0.08%
Quick answer
The Widmark formula estimates BAC from grams of alcohol, bodyweight and a body-water constant, then subtracts about 0.015% per hour of metabolism.
BAC = (grams / (kg x r)) x 100 - 0.015 x hours
How to use the BAC Sober Time Calculator
- 1Count standard drinks: a 14 g drink is 350 ml of 5% beer, 150 ml of 12% wine or 45 ml of spirits.
- 2Enter your weight and the hours since your first drink.
- 3Never drive on an estimate — treat the sober-time figure as a minimum, not a green light.
Worked example
Using the values the calculator loads with:
Inputs
- Body composition constantTypical male (r = 0.68)
- Body weight75 kg
- Standard drinks4 drinks
- Alcohol per drink14 g
- Hours since first drink2 hours
Results
- Estimated BAC now0.08%
- Statusover the 0.05% limit
- Hours to 0.00%5.3
- Hours to under 0.05%2
- Peak BAC reached0.11%
- Total alcohol56 g
- (56 g / (75 kg x 0.68)) x 100 = 0.11% peak
- minus 0.015 x 2 h = 0.08%
Frequently asked questions
How accurate is a BAC estimate?
The Widmark formula is a population average. Food, medication, liver health and drink strength can shift real BAC well above or below the estimate.
Can I speed up sobering up?
No. Coffee, cold showers and food after drinking do not change the metabolism rate of roughly 0.015% per hour.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.