BAC Calculator - Check Your Blood Alcohol Content Instantly

Free BAC Calculator for a fast blood alcohol content estimate. Enter a few basics, get a quick educational result in seconds, and move to the full calculator when you need country legal limits or more drink types.

Quick BAC Calculator

Answer five quick questions and get a fast BAC estimate with less friction.

Drink Type

Number of Drinks

Biological Sex

Body Weight

160

lbs

Hours Since First Drink

hours

Educational estimate only. Never use to decide whether to drive.

Full calculator - country legal limits, more drink types ->

Quick Result

Enter your drinks, weight, and time, then tap calculate to see your BAC estimate.

How This BAC Calculator Works

This BAC Calculator uses the Widmark formula to estimate blood alcohol content from your weight, biological sex, number of drinks, and time since your first drink. The homepage version is a quick BAC Calculator built for speed, so it focuses on the most important inputs first. It gives you a fast educational estimate, not a breathalyzer reading or medical test. If you need a deeper blood alcohol content breakdown, the full BAC Calculator includes more drink types, legal context, and a more detailed result view.

See full methodology ->

BAC Calculator Legal Limits by Country

Blood alcohol content laws vary widely. In the United States and Canada, the standard adult driving limit is often 0.08%, while countries like China and Sweden use 0.02%, and some places use zero tolerance rules. The full BAC Calculator lets you compare your estimate against country-specific thresholds and review the legal context in one place. A legal BAC does not guarantee safe driving, but the full BAC Calculator makes it easier to understand where your estimate stands.

Check legal limits by country ->