BAC Calculator

Estimate blood alcohol concentration from standard drinks, body weight, sex, and time since your first drink, then see how long alcohol may remain in your system.

Drinking Estimate
This tool uses U.S. standard drinks and is educational only. Never use it to decide whether driving is safe.
Estimated BAC
Alcohol affects people differently. This is an estimate, not a safety clearance.
Estimated BAC
0.049
Noticeable impairment
Time to 0.00
3h 16m
Based on a 0.015 BAC reduction per hour
Time to below 0.08
0h 0m
Legal / safety note
Still use caution
BAC calculators are not reliable enough for safety decisions. If alcohol is involved, do not drive.
What counts as a standard drink?
The calculator assumes each drink contains about 0.6 fluid ounces of pure alcohol.
12 oz regular beer
5 oz wine
1.5 oz 80-proof liquor

Frequently Asked Questions