ZovaTool

BAC Calculator

Drinks
Current BAC (Widmark + elimination)
0.000%
Within limits
Peak BAC (Widmark)
0.027%
Peak BAC (Watson TBW)
0.243%
Total alcohol
14.0 g
Stage
Subclinical
Hours to sober
1.8 h
from peak, β=0.015/h
⚠ Estimates only. Never drive after drinking. Tolerance, medications, metabolism, and health conditions all change BAC significantly.

How to use the BAC Calculator

  1. Enter sex, age, height, weight and hours since first drink.
  2. Tap a preset (beer / wine / spirit) or add a custom drink with volume and ABV.
  3. Read peak BAC (Widmark + Watson), current BAC after elimination, stage and time to sober.
  4. Mark "with food" to reduce peak ~15%.
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BAC: the math behind blood alcohol

Widmark (1932) is the standard: BAC = grams of alcohol / (body weight × distribution factor r), where r ≈ 0.68 for men and 0.55 for women.

Watson's TBW (total body water) formula uses age, height and weight to estimate body water directly — usually more accurate, especially for non-average builds.

The body eliminates ~0.015% BAC per hour on average (range 0.010–0.020). Coffee, cold showers and food do NOT speed this up — only time does.

⚠ Use this for education only. Never use it to decide whether to drive — legal and physiological tolerances vary enormously.