Alcohol Units and Grams
Calculate pure ethyl alcohol in grams, standard drinks (10 g), UK units, and alcohol calories.
Open calculatorBreathalyzer (Widmark BAC)
Log each drink’s clock time, volume (mL) and ABV %, then pick a readout hour. Pure ethanol is converted via the Widmark formula (grams ÷ (body weight × r); r = 0.68 for men, 0.55 for women) and eliminated at an average rate of 0.15‰ per hour. Important: This is a simplified mathematical model, not a calibrated breathalyzer — never use it to decide whether you are fit to drive.
kg
Drink log
Add what you drank and when. The quick-select chips pre-fill typical volumes and ABV %.
- ml%
- ml%
ml
%
Food in the stomach, medication, hydration and individual liver metabolism significantly alter real blood-alcohol levels. This page is pure arithmetic — never use it to judge fitness to drive.
Limits in other countries
Standard drivers only. Click a row to switch the gauge threshold.
RiverMath
Estimated BAC (‰)
0.00‰
0.000% BAC
Below 0.80‰ in England, Wales & Northern Ireland — still not a green light to drive
Total ethanol logged28.8 g
Ethanol remaining in body0.0 g
Time until below 0.80‰0 min
Estimated time until 0.00‰0 min
Times are a Widmark estimate rounded up to 15 minutes. Elimination (0.1–0.2‰/h) and absorption vary between people, so the real time may be an hour or two longer. This is not a confirmation of sobriety or a clearance to drive.
Standard passenger-car driver limits (novice and commercial drivers often face lower or 0.00‰ limits). Elimination rate 0.15‰/h is a population average. Sources: ETSC & IARD, 2026.
Since first drink
Recent on this calculator
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Educational estimate only. Not medical, tax, legal or financial advice.