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Time to Sober Calculator

Estimate how long until you are sober.

Result

6.0 h

How it is calculated

The estimate assumes the body clears alcohol at a steady rate of 0.015 BAC (percentage points) per hour. The formula is hours = BAC ÷ 0.015, shown with one decimal and the unit h. BAC is entered as a percentage figure such as 0.08, the common way of quoting blood alcohol in many countries; some countries use other units or lower legal limits. The 0.015 rate is an average. Real elimination varies with liver function, body size, food and other factors, and the tool does not model absorption, so it is not safe to use as proof you can drive.

Worked example

You have a BAC of 0.09. Dividing by the assumed elimination rate gives 0.09 / 0.015 = 6. The tool shows 6.0 h. That means about six hours until the estimated level reaches zero. If you started from 0.04, the same formula gives 0.04 / 0.015 = 2.7 hours, so the time is directly proportional to the starting level.

Try this example →

Common mistakes

  • Using the result to decide whether it is legal or safe to drive; the figure is a rough average and impairment can last longer.
  • Entering the BAC in the wrong unit, such as mg/dL or per mille instead of the percent figure the tool expects.
  • Counting from the first drink instead of from the moment the BAC was measured or estimated.
  • Assuming coffee, a shower or food speed up the removal; the clearing rate stays roughly constant.

About this calculator

This calculator estimates how long it takes for blood alcohol concentration (BAC) to return to zero, based on the average elimination rate of roughly 0.015% per hour that the liver metabolizes alcohol (the Widmark-based rule of thumb used in alcohol education). Enter your current or estimated BAC to see the approximate hours until you're sober.

It's used by students and drinkers who want a rough safety check before deciding whether to drive, and by bartenders, event staff, and health educators explaining how alcohol clears the body. The elimination rate varies by person, so the result is an estimate, not a guarantee of legal sobriety.

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