Blood Alcohol Content Estimator
Estimate blood alcohol concentration from what you have actually drunk, using the Widmark formula plus the Watson and Seidl total-body-water refinements, and see how it decays over the hours that follow.
Never use this number to decide whether you can drive. It is a rough estimate from averages: real BAC depends on food, hydration, drinking speed, body composition, medication, genetics and how your liver happens to be working today, and it can be double or half what is shown here. Only a calibrated breathalyser or a blood test measures BAC. If you have been drinking, do not drive — and if you feel impaired at all, the estimate is already irrelevant.
1. About you
2. What you have drunk
Add each drink. Pure alcohol in grams = volume (ml) x ABV x 0.789, the density of ethanol.
Custom drink
No drinks logged yet. Add at least one to see an estimate.
About this tool
The Widmark formula divides the grams of alcohol you drank by your body weight times a distribution factor r, the fraction of body mass that is water. The original r is a fixed 0.68 for men and 0.55 for women; the Watson and Seidl refinements estimate your total body water from height, weight, age and sex instead, which is why they disagree. Alcohol is then eliminated at an average 0.015% per hour. Everything is calculated in your browser and nothing is stored or sent anywhere.
- 100% free — no account needed
- Runs in your browser
- Nothing is uploaded
Frequently asked questions
Is Blood Alcohol Estimator really free?
Yes. Blood Alcohol Estimator is completely free on PureBrowser — every feature, with no account, no trial, and no credit card.
Does Blood Alcohol Estimator upload my data?
No. Blood Alcohol Estimator runs entirely inside your browser, so anything you type, paste, or open stays on your own device.
Do I need to sign up or install anything?
Neither. There is no account and nothing to download — open the page and Blood Alcohol Estimator is ready to use on desktop or mobile.
Does Blood Alcohol Estimator work offline?
Once the page has loaded, yes. All of the processing happens locally in your browser, so it keeps working without a connection.
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