ffee All tools
EN 中文 FR DE

Blood Alcohol Calculator

Estimate blood alcohol content with the Widmark formula and see the hours until you reach zero.

Blood alcohol estimate

Blood alcohol content: —
Legal limit: —
Already eliminated: —
Hours to sobriety: —
An estimate for general information and not medical advice. Never use it to decide whether to drive.

How to use the Blood Alcohol Calculator

  1. Select your sex and enter your body weight.
  2. Add the number of drinks, their strength and their volume.
  3. Enter the hours since your first drink to see the estimate.

Features

Advertisement

More tools

Body Fat Calculator BMR Calculator TDEE Calculator Ideal Weight Calculator Water Intake Calculator Macro Calculator Protein Intake Calculator One Rep Max Calculator Running Pace Calculator Heart Rate Zones Sleep Cycle Calculator Ovulation Calculator

Frequently Asked Questions

Common questions about the free online blood alcohol calculator.

The tool uses the Widmark formula: alcohol in grams divided by body weight in grams times the Widmark factor for your sex.
It estimates how much of your body is water: about 0.68 for men and 0.55 for women, which changes the resulting blood alcohol.
Volume in millilitres times alcohol by volume times 0.789, the density of ethanol, gives grams of pure alcohol per drink.
The model removes about 0.015 percent blood alcohol per hour, which is a common population average used in estimates.
The estimated blood alcohol is divided by the elimination rate, so it is the time until the estimate reaches zero.
It compares against 0.08 percent, the common limit for driving in many places, but local laws differ and can be lower.
No. It is an estimate for general information and not medical advice. If you have been drinking, do not drive.
Food, hydration, genetics, medication and drinking speed all shift real blood alcohol, so any calculation is only approximate.

Last updated: October 10, 2026