BAC Calculator
Estimate blood alcohol content and impairment
Use this when you need a fast, accurate result — no sign-up, works entirely in your browser.
Estimated BAC (%)—
Impairment level—
Hours until sober—
How to Use
- Enter your details into the fields above.
- Click the calculate button to get your result instantly.
- Use the clear button to start a new calculation.
Example
- 4 standard drinks, 160 lbs, male, 2 hours elapsed → BAC ≈ 0.011% — no significant impairment
- 4 drinks, 180 lb male, 1 hour → BAC ≈ 0.022% (mild relaxation); sober in ≈ 1.5 hours
Formula
Widmark formula: BAC% = (alcohol grams / (weightlbs × r)) × 0.806 / 10, where r = 0.68 for males and 0.55 for females, and one US standard drink contains about 14 g of pure alcohol. The body metabolizes roughly 0.015% per hour. This is an estimate only — never use it to decide whether you can drive.
About BAC Calculator
Estimate blood alcohol content and impairment. This free online tool gives you fast, accurate results without registration or downloads.
Everything runs locally in your browser, so your data is never uploaded or stored — privacy first.
Frequently Asked Questions
Is this tool free to use? +
Yes, it is completely free with no registration or download required.
Is my data private? +
Yes. Everything is processed locally in your browser. Nothing is uploaded or stored on our servers.
Does it work on mobile? +
Yes, it works on any device — phone, tablet, or desktop.