Understanding alcohol & your body
The science behind Blood Alcohol Content — how your body processes alcohol, and why most calculators get it wrong.
How BAC Works
What Blood Alcohol Content actually measures, how your body processes alcohol, and why most BAC calculators get it wrong.
Read more →Alcohol & Your Body
How alcohol is absorbed, what affects your metabolism rate, and why body composition matters more than weight alone.
Read more →BAC Chart
Estimated BAC levels by weight, sex, and number of drinks. See where your limit might be before you go out.
View chart →Things most people don’t know about BAC
Many BAC calculators can’t see body fat
Classic formulas work from your weight — some also from height, age and sex. But alcohol spreads through body water, and lean tissue holds far more water than fat. Two people of the same build can carry very different amounts of fat, and those formulas can’t tell them apart.
Body fat percentage matters more than weight
Two people weighing 180 lbs can have wildly different BAC levels from the same drinks. An athletic person (12% body fat) and someone with 35% body fat dilute alcohol into very different volumes.
One model doesn’t fit every population
South Asian adults tend to carry more body fat at the same BMI than Western reference groups, so Alcophone runs a separate South Asian model for users in India — and compares your BAC with the legal limit of your own country.
Your liver processes alcohol at ~0.015% per hour on average
It varies from person to person (roughly 0.010–0.025% per hour); sex and drinking history matter, body weight does not. No amount of coffee or water will speed it up once alcohol is in your blood; a real meal makes it run somewhat faster, but never enough to make driving safe. The only cure is time.
The legal limit isn’t a safe limit — impairment starts at 0.02%
Reaction time, judgment, and coordination begin declining well below the legal limit. That’s why Alcophone tracks five risk levels, not just “legal” or “over.” And 0.08% is only the US number — it’s 0.05% in Canada, Australia, Ireland and Scotland, 0.03% in India. See the limit tables by country →

