Estimate blood alcohol concentration (BAC) from the drinks you entered, your body weight, sex, and how long it has been since the first drink. The result is a Widmark estimate with a simple hourly fade toward 0% — useful for learning how dose, body size, and time interact, not for deciding whether someone is safe to drive.
Formula
The US Widmark form used here (same goldens as calculator.net):
oz_alcohol = servings × serving_fl_oz × (ABV / 100)
r = 0.73 if male, 0.66 if female
BAC% = (oz_alcohol × 5.24) / (weight_lb × r) − 0.015 × hours
Pounds use the conversion.js factor 1 lb = 0.453592 kg. Kilograms and
grams are converted to pounds before the formula. BAC below zero is shown
as 0%. Hours remaining to 0% are BAC / 0.015, rounded up.
Labeled-ounce servings (12 oz beer, 5 oz wine, 0.5 oz / 1 oz shots) use the ounce on the label. Milliliter-only bottles follow calculator.net's two approximations: 250 / 500 / 1000 mL at 34 US fl oz per liter, and other mL sizes at 30 mL per oz. The 1.5 oz / 50 ml shot uses the 50 mL side of that label.
This is an educational estimate, not a breathalyzer, a medical diagnosis, or legal advice. If you have been drinking, do not drive. Impairment can start well below 0.08%, and only a properly administered test measures BAC for legal purposes.
Typical effects by BAC
Ranges below are the same population descriptions calculator.net lists. People vary widely; treat them as a rough map, not a personal forecast.
| BAC (%) | Typical effects |
|---|---|
| 0.001–0.029 | Average individual appears normal |
| 0.030–0.059 | Mild euphoria, relaxation, talkativeness, decreased inhibition |
| 0.060–0.099 | Euphoria, reduced pain sensitivity; reasoning and peripheral vision suffer |
| 0.100–0.199 | Boisterousness; slower reflexes, slurred speech, staggering |
| 0.200–0.299 | Nausea, emotional swings, blackouts, possible loss of consciousness |
| 0.300–0.399 | Stupor; breathing and heart rate can be affected |
| 0.400–0.500 | Coma; possibility of death |
| above 0.50 | High possibility of death |
Examples
Default: 155 lb man, two 12 oz 5% beers, 2 hours
Two 12 oz beers at 5% ABV are 1.2 oz of alcohol. Peak BAC is about 0.056%. After two hours at 0.015%/h the estimate is 0.026%, with around 2 more hours to reach 0%. Typical effects at that level: appears normal.
Same drinks, 155 lb woman
The female r factor (0.66 vs 0.73) raises the same 1.2 oz of alcohol to a peak near 0.061%. Two hours later the estimate is 0.031% (mild euphoria), with around 3 more hours to 0%.
One 12 oz 5.8% beer, 80 kg man, just finished
At time zero the estimate is 0.028%, fading to 0% in a little under 2 hours. Swapping the same serving to a 1 L 5% beer raises BAC to about 0.069%.