Widmark Sober Time
Calculator

It starts from an estimated blood alcohol concentration (often derived from the Widmark formula) and divides it by the average rate the body eliminates alcohol, typically around 0.015 to 0.020 BAC per hour, to estimate the time needed to reach zero or a specific target BAC. This gives a rough timeline based on population averages.

Alcohol is metabolized primarily by the liver at a relatively fixed rate that isn't significantly sped up by coffee, cold showers, exercise, or other common myths; the liver simply processes a set amount per hour regardless of these interventions. This is why time is truly the only reliable way to lower BAC.

Because alcohol elimination rate varies between individuals based on liver function, genetics, chronic alcohol use, food intake, and other factors, the actual time to reach a safe BAC can differ meaningfully from the estimate. This calculator should never be used to determine whether it's legal or safe to drive.

The estimate assumes all the alcohol has already been fully absorbed into the bloodstream, but if you've been drinking recently, your BAC may still be rising rather than falling, which would make the sober-time estimate inaccurate until absorption is complete. This is an important limitation, especially soon after the last drink.

The only safe approach is to not drive at all if there's any doubt, and to arrange alternative transportation, since no calculator or personal judgment can reliably substitute for a breathalyzer test or simply waiting a generous, conservative amount of time. This tool is for general education only, never for making that decision.