Blood Alcohol Content Calculator

This calculator gives a rough estimate of blood alcohol content (BAC) using the widely referenced Widmark formula. It's for educational purposes only and should never be used to decide whether it's safe to drive — always err on the side of caution.

Estimated BAC
Standard Drinks
Total Alcohol (grams)
Estimated BAC (%)

About this calculator

Estimate your approximate blood alcohol content (BAC) based on drinks consumed, body weight, sex, and time elapsed.

Frequently Asked Questions

How accurate is this BAC calculator?

This tool provides a rough estimate using the Widmark formula. Actual BAC varies based on metabolism, food intake, medications, and other individual factors.

What counts as one standard drink?

A standard drink is typically 12 oz of regular beer, 5 oz of wine, or 1.5 oz of distilled spirits — each containing about 14 grams of pure alcohol.

Can I use this to decide if I'm safe to drive?

No. This calculator is for educational purposes only. Never rely on a BAC estimate to determine if you're safe to drive — always arrange a sober ride if you've been drinking.