⚠ For education only — not a safety or driving decision tool
This calculator gives a rough estimate, not a measurement. It cannot tell you whether you're safe or legal to drive. The only way to know your actual BAC is a breathalyzer or blood test. If you've been drinking, don't drive — use a rideshare, taxi, or designated driver, no matter what number this shows.
Your details
One standard drink ≈ 12 oz beer (5% ABV), 5 oz wine (12% ABV), or 1.5 oz spirits (40% ABV). Many cocktails and craft beers contain more than one standard drink.
0.000%
estimated blood alcohol content
General reference ranges
Signs of alcohol poisoning (seek emergency help immediately): confusion or unresponsiveness, vomiting while unconscious, slow or irregular breathing, seizures, pale or blue-tinged skin, low body temperature. Don't wait for all symptoms — call emergency services if you suspect alcohol poisoning in yourself or someone else.
Curious about the calories in what you're drinking? Check the Calorie Tracker.
⚠ This is not a safety or legal determination.
Never use this number to decide whether to drive. Actual impairment and legal risk don't depend only on BAC — and this estimate can be meaningfully wrong for your specific body and situation. If you've had anything to drink and might drive, choose not to. Arrange a ride instead.
How it works
We estimate total alcohol consumed from your number of standard drinks.
We apply the Widmark formula, which factors in your body weight and biological sex (which affects average body water distribution).
We subtract elimination over time, using a standard average metabolism rate of about 0.015% per hour.
The result is a rough estimate — not a measurement, and not something to base a driving decision on.
Real BAC depends on factors this formula can't measure: food in your stomach, medications, individual metabolism, drink strength, and more. Treat this as educational context only.
Frequently asked questions
No. This is an educational estimate only. Actual BAC is affected by many factors this formula can't account for, and can be significantly wrong in either direction. The only safe choice after drinking is not to drive — use a rideshare, taxi, or designated driver instead.
The Widmark formula, a standard method from forensic toxicology that estimates BAC from alcohol consumed, body weight, biological sex, and time elapsed. It's a population-average estimate, not a personalized measurement.
In the US, about 14 grams of pure alcohol — roughly a 12 oz beer at 5% ABV, a 5 oz glass of wine at 12% ABV, or a 1.5 oz shot of spirits at 40% ABV. Many drinks contain more than one standard drink.
Because the Widmark formula relies on population-average constants that don't capture individual variation — body composition, stomach contents, medications, liver function, and drink strength all affect real BAC. This is exactly why the estimate should never be used to judge whether you're safe or legal to drive.