Estimated Blood Alcohol Content, using the Widmark formula.
This is a rough estimate only, not a measurement — individual metabolism varies widely. Never use this to decide whether it's safe to drive; if you've been drinking, don't drive.
It uses the Widmark formula: total alcohol grams (drinks × grams per drink) divided by your body weight times a sex-specific distribution ratio (0.68 for men, 0.55 for women), then reduces that by an assumed elimination rate of 0.15‰ per hour since you started drinking.
The distribution ratio (r) approximates how alcohol spreads through body water, which differs on average between men and women, so the same amount of alcohol and body weight produces a different estimated BAC for each.
It divides your current estimated BAC (in per-mille) by the assumed elimination rate of 0.15‰ per hour. As the warning below the result states, this is a rough estimate only — never use it to decide whether it's safe to drive.