Blood Alcohol Calculator
Calculate your estimated blood alcohol concentration (BAC) based on your weight, gender, drinks consumed, and time elapsed.
Category: Fitness & Health
Important Disclaimer
Standard Drink Reference
Beer (5% ABV)
12 oz (355 ml)
Wine (12% ABV)
5 oz (148 ml)
Spirits (40% ABV)
1.5 oz (44 ml)
Each of these contains approximately the same amount of alcohol (~14g).
Frequently Asked Questions
What is BAC and how is it measured?
Blood Alcohol Concentration (BAC) measures the percentage of alcohol in your bloodstream. For example, 0.08% BAC means there are 0.08 grams of alcohol per 100 milliliters of blood. It can be measured through breath tests (breathalyzers), blood tests, urine tests, or estimated through formulas that consider weight, gender, alcohol consumed, and time elapsed.
What is the legal BAC limit for driving?
In most U.S. states and many countries, the legal BAC limit for driving is 0.08%. However, some countries have lower limits (0.05% or even 0.02%), and many places have 'zero tolerance' laws with lower limits for drivers under 21 or commercial drivers. Even below legal limits, alcohol can impair driving ability.
How accurate are BAC calculators?
BAC calculators provide estimates based on formulas like the Widmark equation, but individual factors can cause significant variations. Metabolism rates, food consumption, medications, health conditions, and tolerance levels all affect how alcohol impacts your system. These calculators should be used as educational tools, not as definitive measures of intoxication or legal compliance.
How long does it take for alcohol to leave your system?
On average, the human body metabolizes alcohol at a rate of about 0.015% BAC per hour (roughly one standard drink per hour), though this varies by individual. For example, if your BAC is 0.08%, it would take approximately 5.5 hours to return to 0%. No amount of coffee, cold showers, or other remedies will speed up this process significantly.