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BAC Calculator

Estimate blood alcohol content from drinks, weight, and time.

This is an educational estimate, not a breathalyzer, and it cannot tell you whether you are safe to drive. Only a calibrated device can do that, and never drive after drinking.

Body water differs, so the same drinks affect different people differently.

A standard drink is one of

  • 12 fl oz (355 ml) of 5% beer
  • 5 fl oz (148 ml) of 12% wine
  • 1.5 fl oz (44 ml) of 40% spirits

Estimated BAC now

0.00%

At the peak

0.00%

Hours to near zero

0

What that means

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What Is BAC Calculator?

The BAC Calculator estimates blood alcohol content from the number of standard drinks, body weight, sex, and time elapsed, using the Widmark equation and a standard elimination rate.

Who Uses the BAC Calculator?

People use it as a rough educational reference for how drinks and time affect BAC levels. It is not a substitute for a breathalyzer.

How to Use the BAC Calculator

  1. Enter your sex and body weight.
  2. Enter the number of standard drinks.
  3. Enter how many hours have passed.
  4. Read the estimated BAC and the reference scale.

Why Choose Our BAC Calculator?

  • Standard drink sizes listed
  • Shows peak and elapsed-time estimates
  • Reference scale for the US legal limit

Try the BAC Calculator above — it is free, fast, and works on any device. Bookmark this page to return whenever you need it.