EDUCATIONAL BAC TOOL

BAC Calculator
over time.

See how a Widmark-style BAC estimate changes across future hours from standard drinks, body weight, and elapsed time. This is a model illustration, not a personal measurement or a countdown to driving.

Need to add individual drinks first? Use the BAC Calculator →

ESTIMATED RANGE

How does an estimate change over time?

Set the model inputs

The model uses a fixed metabolism assumption. Actual BAC can differ substantially.

HOW TO READ THIS

A model is not
a measurement.

The estimate uses total pure alcohol, weight, sex used in the formula, and elapsed time. It applies the same fixed hourly assumption to every future row, which is why it cannot account for individual absorption, food, medication, health, or metabolism.

Explore the BAC chart and uncertainty
Read the BAC formula and limits
Learn about alcohol metabolism

What a BAC calculator over time can show

This tool applies the site's educational Widmark-style model to the standard drinks you enter, then displays the current estimated range and the same model at future hourly points. It is useful for seeing how the model's arithmetic changes when elapsed time changes.

What it cannot tell you

It cannot measure BAC, predict a personal sober time, confirm a legal limit, or decide whether you can drive. Food, drink timing, absorption, medication, health, body composition, and individual metabolism can all make a real result different from the model. Only a properly administered breath or blood test can measure BAC.

Do not treat a future row as permission to drive. If alcohol is involved, choose a sober driver, public transport, a taxi/rideshare, or another safe way home.

Start with the right input

If you know a beer, wine, spirit, or container label, first use the standard drinks calculator or standard drinks per container calculator. If you want to add individual drink details directly, use the main BAC Calculator. To understand the formula and its limits, read the methodology; for a plain-language explanation, read what BAC means.

Sources and review

  1. National Highway Traffic Safety Administration: drunk driving and BAC
  2. The BAC Calculator: formula, assumptions, and limits