BAC Calculator
Estimate blood alcohol content from drinks, weight and time — with clear safety warnings.
1 standard U.S. drink ≈ 12 oz beer (5%), 5 oz wine (12%) or 1.5 oz spirits (40%).
Warning:This is a rough estimate only — real BAC varies widely with food, metabolism, medications and drink strength, and impairment starts well below 0.08%. Never use this to decide whether you can drive. If you've been drinking, don't drive — period. Not medical or legal advice.
What Is the BAC Calculator?
The BAC Calculator estimates blood alcohol concentration using the Widmark formula from your weight, sex, standard drinks consumed and hours elapsed. It shows the estimated level, what it typically means for impairment, and roughly how long until you're back to zero. Everything is calculated locally.
How It Works
Enter your details and drinks. One standard U.S. drink is 12 oz of 5% beer, 5 oz of wine or 1.5 oz of spirits.
When to Use It
Use it for education — understanding how drinks, body weight and time interact. Never use it to decide whether you can drive.
Frequently Asked Questions
- Can I use this to know if I'm safe to drive?
- No. Real BAC varies widely with food, medications, metabolism and pour sizes, and impairment starts well below the legal limit. If you've been drinking, don't drive.
Last reviewed: 2026-06-27