Kalkulo

Blood alcohol calculator

Estimate your blood alcohol concentration with the Widmark formula against the 0.08% BAC limit. Educational only, never a basis for deciding to drive.

Result
0.061 %BAC
Below legal limit (0.08 %BAC)
Time to full elimination: ~4.1 h
Indicative only. Never drink and drive.

About this tool

Why use this tool

The BAC (Blood Alcohol Concentration) calculator estimates alcohol level in the bloodstream expressed as %BAC (g/dL), the standard US unit. It raises awareness of the federal legal limit of 0.08 %BAC for drivers 21+ in all 50 states (0.05 %BAC in Utah), and zero tolerance (0.00–0.02 %BAC) for drivers under 21 under state Zero Tolerance laws.

How the calculation works

Widmark formula: BAC(g/L) = alcohol(g) ÷ (weight(kg) × r), with r = 0.7 for men, 0.6 for women. Convert to %BAC by dividing by 10. A US standard drink contains 14 g of pure alcohol (NIAAA definition): 12 oz beer at 5 %, 5 oz wine at 12 %, or 1.5 oz spirits at 40 %. Average liver metabolism is about 0.015 %BAC per hour.

Real example

A 180 lb (81.6 kg) man drinking 3 standard drinks over 1 hour: 3 × 14 = 42 g alcohol. BAC = 42 ÷ (81.6 × 0.7) = 0.735 g/L = 0.074 %BAC — approaching but below 0.08. A 130 lb (59 kg) woman with the same 3 drinks: 42 ÷ (59 × 0.6) = 1.19 g/L = 0.119 %BAC — well above the legal limit.

Practical tips

Never drive after drinking. Use a designated driver, rideshare (Uber, Lyft), taxi or public transit. Coffee, cold showers and exercise do NOT speed up alcohol elimination — only time does. Eat before and during drinking, alternate with water. The NHTSA reports that alcohol-impaired driving kills over 13,000 people annually in the US. Under implied consent laws, refusing a breathalyzer results in automatic license suspension in most states.

Disclaimer

This tool is educational only. Widmark's formula does not account for absorption rate, food intake, medications, fatigue, hormonal cycle or liver conditions. Penalties for DUI/DWI vary by state and typically include license suspension, fines up to $10,000, mandatory alcohol education, ignition interlock devices and potential jail time. Never rely on this calculator to decide whether to drive. If you struggle with alcohol, call SAMHSA's National Helpline: 1-800-662-4357.

Frequently asked questions

What counts as one standard drink in the US?⌄
The NIAAA defines a US standard drink as 14 grams of pure alcohol: a 12 oz regular beer at 5% ABV, a 5 oz glass of wine at 12% ABV, or a 1.5 oz shot of 80-proof spirits. Craft beers and mixed cocktails often contain more alcohol than these reference sizes, so a single serving can equal more than one standard drink.
How long does it actually take to become sober after drinking?⌄
There is no way to speed up sobering up — the liver metabolises alcohol at a fairly fixed rate of roughly 0.015% BAC per hour on average, regardless of coffee, cold showers, exercise or sleep. The only reliable way to reach zero is to let enough time pass, which is why the calculator's elimination estimate should be treated as a rough floor, not a guarantee.
Does eating food slow down alcohol absorption?⌄
Yes. Food in the stomach, especially fat and protein, delays how quickly alcohol reaches the bloodstream and lowers the peak BAC compared with drinking on an empty stomach, though it does not reduce the total amount of alcohol eventually absorbed. Eating before and during drinking is one of the few evidence-based ways to blunt intoxication.
What is the legal BAC limit for driving in the US?⌄
The limit is 0.08% BAC for drivers 21 and over in all 50 states, with a lower 0.05% limit in Utah since 2018, and zero-tolerance laws setting limits near 0.00-0.02% for drivers under 21. These are legal per se limits — you can still be charged with impaired driving below them if your ability to drive is visibly affected.
Can this calculator replace a breathalyzer before deciding to drive?⌄
No. The Widmark formula behind this estimate does not account for your exact absorption rate, medications, fatigue, hormonal factors or liver function, so the result can be meaningfully off from your true BAC. It is an educational tool only — the only responsible choice after drinking is not to drive, regardless of what the estimate shows.

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