BAC Calculator – Free Blood Alcohol Content Estimator
BAC Calculator is a free online blood alcohol concentration estimator from SafeBAC.org that predicts your BAC from the drinks you consumed, your body weight, and the time since your first drink.
What is BAC Calculator?
BAC Calculator is a browser-based tool that estimates blood alcohol concentration (BAC) as a percentage. You input sex, body weight in kilograms, country or region, time since your first drink, and each drink's type (beer, wine, spirits, or other), serving size in milliliters, and ABV percentage; it outputs an estimated BAC, a safety overview, and a comparison with commonly cited legal limits for your selected region.
The calculator runs entirely in your browser; the page states that no drink details are stored or sent to servers. It is published by SafeBAC.org, which also offers related tools such as a BAC time-to-zero calculator and a printable BAC chart.
Key Features
- Free web-based calculator — No account or download required; estimates are produced in the browser and data is not stored.
- Drink-by-drink input — Add multiple drinks with type (beer, wine, spirits, other), serving count, serving size in mL, and ABV percentage.
- Country/region legal limit comparison — Select from United States, United Kingdom, Australia, Canada, New Zealand, Morocco, or Algeria to see your estimated BAC against common legal driving limits.
- Printable BAC chart by weight and gender — A printable table shows estimated BAC for body weights from 100 to 240 lbs and 1 to 8 drinks, using standard drink sizes (1.5 oz spirits, 5 oz wine, or 12 oz beer).
- Clear safety guidance — Results include low-risk, driving-impaired, and legally intoxicated categories, plus a prominent warning never to drive after drinking.
- Related tools — Links to a separate time-to-zero calculator, an advanced calculator, a women-specific calculator, and a BAC conversion calculator.
Who is it for?
BAC Calculator is for anyone who wants to understand how alcohol intake and body weight affect blood alcohol concentration.
- Social drinkers — Estimate their BAC after a party to see why driving is unsafe.
- Students and educators — Use the printable BAC chart in health classes to demonstrate the effects of weight, gender, and number of drinks.
- People comparing legal limits — Check estimated BAC against the selected region's driving limit (US, UK, Australia, Canada, New Zealand, Morocco, Algeria) before deciding on a ride home.
- Curious individuals — Learn how alcohol is processed over time by entering different drink amounts and elapsed times.
What can you do with BAC Calculator?
- Estimate personal BAC — Enter your details and drinks to see an approximate BAC percentage and safety category.
- Compare with legal limits — Choose your country to see if the estimate falls below, near, or above commonly cited BAC limits for driving.
- Print a reference chart — Download the free BAC chart by weight and gender to check typical levels without using the calculator.
- Link to related tools — Jump to time-to-zero estimation, an advanced calculator, or a women-specific calculator to explore more scenarios.
How does BAC Calculator work?
BAC Calculator uses standard BAC estimation formulas based on sex, body weight, total alcohol consumed, and elapsed time since the first drink.
- Select sex, enter body weight, and choose a country/region.
- Add one or more drinks, specifying type, number of servings, serving size, and ABV.
- Enter time since your first drink in hours/minutes.
- Click "Estimate BAC" to see the estimated percentage and safety message.
The page emphasizes results are only estimates; actual BAC varies with metabolism, health, medications, and other factors.
BAC Calculator FAQ
Is BAC Calculator free to use?
Yes, the tool is free online, and the printable BAC chart is also provided at no cost. No payment or subscription is required.
Can I use BAC Calculator to decide if I can drive?
No. The page explicitly warns: "Never use BAC estimates to decide whether you can drive." If you have been drinking, choose a taxi, rideshare, public transport, or a sober driver.
Does BAC Calculator store my data?
No. All calculations run in your browser, and the site states it does not store or send your drink details to its servers.
Why do women often reach higher BAC than men?
Because of differences in body composition and alcohol distribution, women typically have a higher BAC than men after consuming the same amount of alcohol, even at the same body weight.
What is BAC time to zero?
It is an estimate of how long your body may take to process alcohol and return to 0.00%. Even when that estimate says zero, you may still feel alcohol's effects, so you should not drive.
The calculator is available at https://safebac.org/.
