Estimate standard alcohol units and a rough blood alcohol concentration (BAC) from what you've had to drink. For general awareness only — never use this to decide whether it's safe to drive.
Enter your details above for an estimate.
The Widmark formula used here is a widely cited approximation, not a precise measurement. Food in your stomach, medications, liver function, hydration, and individual metabolism can all shift your actual BAC well away from this estimate.
A UK unit is 10ml (8g) of pure alcohol. A US standard drink is defined as 14g (about 0.6 fl oz) of pure alcohol — different countries define a "standard drink" differently, which is why both are shown.
No. Never use this or any estimate to decide whether to drive after drinking — the only safe BAC behind the wheel is zero. If you've had any alcohol, arrange a taxi, rideshare, or a sober driver in advance.
The Widmark formula uses a body-water distribution ratio that differs, on average, between men and women, affecting how alcohol is diluted in the body. It's a population average, not a precise value for any individual.
