Blood alcohol calculator
Estimate your blood alcohol concentration and how long your body takes to clear the drinks, with the Widmark formula. When in doubt, don't drive.
How long does alcohol stay in your blood?
Everything happens on your device: nothing is uploaded to the internet.
If you drink, don’t drive. This calculator is only an estimate and must not be used to decide whether you can drive.
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Blood alcohol calculator: what it is for
Enter your weight, sex, the drinks you had and how long ago you started drinking. The calculator estimates your blood alcohol concentration, the peak, the breathalyzer equivalent and how long until your body clears it all.
The result is only educational: every body reacts differently.
How to use
- Fill in weight, sex and hours.
- Enter the amount of each drink.
- See the estimate and the time to zero.
When to use it
- Understand how long alcohol stays in the body.
- Raise awareness of the risks of drinking and driving.
- Plan getting home without driving.
Frequently asked questions
Can I use the calculator to know if I can drive?
No. Every body reacts differently and the result is only an educational estimate. If you've been drinking, don't drive: use a rideshare, a taxi or a driver who hasn't been drinking.
How does the body eliminate alcohol?
The liver removes, on average, about 0.15 gram of alcohol per liter of blood per hour. Coffee, a cold shower or eating after drinking don't speed this up.
What is the Widmark formula?
It is the classic formula to estimate blood alcohol: grams of alcohol divided by body weight times a distribution factor (about 0.68 for men and 0.55 for women), minus what has already been eliminated over time.
Is it really free?
Yes, 100% free. No sign-up, no subscription and no usage limits. All Tools123 tools are free and run right in your browser.