BAC Calculator
Estimate your Blood Alcohol Content based on drinks consumed, body weight, and time elapsed.
Your Information
Gender
Unit
Body Weight
lb
Number of Drinks
Drink Type
Hours Since First Drink
hrs
Your BAC Estimate
Estimated Blood Alcohol Content
0.000
%
Sober
0.00%
Sober 0.05%
Buzzed 0.08%
Legal Limit 0.15%
Impaired 0.30%+
Danger
Sober 0.05%
Buzzed 0.08%
Legal Limit 0.15%
Impaired 0.30%+
Danger
Estimated Time Until Sober (0.00%)
0h 0m
⚠️ Warning: This is an estimate only. Never drive after drinking. BAC varies based on food intake, medications, metabolism, and other factors. Legal limit in most US states is 0.08%. Some states have lower limits for commercial drivers (0.04%) and zero tolerance for under 21.
How BAC is Calculated
BAC is calculated using the Widmark formula, which accounts for the amount of alcohol consumed, body weight, gender (men and women metabolize alcohol differently), and time elapsed.
One “standard drink” in the US contains about 14 grams of pure alcohol: 12oz beer (5%), 5oz wine (12%), or 1.5oz spirits (40%). Your body metabolizes alcohol at approximately 0.015% per hour.
Understanding BAC Levels
- 0.02-0.03%: Slight mood elevation, relaxation. Minimal impairment.
- 0.05-0.06%: Lowered inhibitions, minor impairment of reasoning and memory.
- 0.08-0.10%: Legal intoxication in most states. Impaired balance, speech, reaction time.
- 0.15-0.20%: Major impairment. Difficulty walking, blurred vision, slurred speech.
- 0.30%+: Medical emergency risk. Loss of consciousness possible.
Factors Affecting BAC
- Body weight: Higher weight generally means lower BAC from same amount of alcohol.
- Gender: Women typically have higher BAC due to different body composition and enzymes.
- Food intake: Eating before or while drinking slows alcohol absorption significantly.
- Drink rate: Faster drinking leads to higher peak BAC before metabolism catches up.
Important Safety Information
- Never drive impaired: Even below 0.08%, alcohol impairs judgment and reaction time.
- Plan ahead: Designate a sober driver, use rideshare, or stay overnight.
- Individual variation: This calculator provides estimates. Actual BAC varies significantly.
- Medication interactions: Many medications intensify alcohol effects. Check with your pharmacist.