Updated Alcohol Estimate

BAC Calculator

Estimate blood alcohol content (BAC), see drink-based BAC, estimate time to sober, and compare against a legal limit. For educational use only.

Estimated BAC Time to Sober Drink Breakdown Legal Limit Check

Multi-Tool BAC Calculator

Switch between standard BAC estimate, drink-based BAC, time to sober, and legal limit comparison. Results are approximate and should not be used to decide if you can drive.

This is a rough estimate based on population averages. Individual BAC can vary widely. Never rely on this tool to decide whether you can drive, work, or perform any safety-critical activity.

Standard drink estimates assume approximately 14 g of pure alcohol per drink. Actual values vary by brand and pour size.

Elimination rates vary between individuals and situations. This is only a rough estimate and should not be used to decide when it is safe to drive or operate machinery.
Legal limits differ by country, state, age, and license type. Always check your local laws. Staying below a legal limit does not guarantee you are safe or unimpaired.

BAC Calculator – Blood Alcohol Content, Time to Sober & Legal Limit

This BAC Calculator provides rough estimates of blood alcohol content (BAC) based on body weight, gender, amount of alcohol consumed, and time since drinking started. It also estimates how long it may take for BAC to drop and lets you compare against a chosen legal limit.

Important Safety Disclaimer

This tool is for educational purposes only. It does not account for all individual factors, and results can be significantly inaccurate for any given person. Never use this calculator to decide whether you should drive, operate machinery, work, or perform any task where impairment is dangerous. If you have consumed alcohol, the safest choice is not to drive.

How BAC Is Estimated

Many BAC calculators use a version of the Widmark formula. In simplified form, it estimates BAC using total alcohol consumed, body weight, a gender-based body water constant, and time for elimination:

BAC ≈ (A / (r × W)) × 100 − β × t

A is grams of pure alcohol, W is body weight in kilograms, r is a body water constant (often around 0.68 for men and 0.55 for women), β is an average elimination rate, and t is hours since drinking began. This calculator uses typical population averages and converts drink volume and ABV into grams of alcohol.

Grams of Pure Alcohol

Pure alcohol in grams is often approximated using the volume of the drink, its alcohol percentage, and the density of ethanol:

Grams of Alcohol ≈ Volume (ml) × ABV × 0.789 ÷ 100

Elimination Rate and Time to Sober

The body metabolizes alcohol over time. A often-cited average elimination rate is about 0.015 BAC per hour, but this can vary widely between individuals. The Time to Sober tab lets you choose both your current BAC estimate and an elimination rate to approximate how many hours it might take to reach a chosen target BAC.

Legal Limits Vary by Region

Common driving BAC limits in many places range from 0.02 to 0.08, but laws change and can be stricter for novice drivers, commercial drivers, or specific age groups. The Legal Limit tab intentionally uses a manual input so you can set your own reference value and always check your local regulations.

How to Use This BAC Calculator

  • Use Standard BAC when you know your total alcohol intake (volume and ABV) and want a quick estimate by weight and gender.
  • Use Drink-Based BAC to estimate BAC from typical beer, wine, and spirits servings.
  • Use Time to Sober when you have an estimated BAC and want to see how long it may take to approach a lower level.
  • Use Legal Limit Check to compare your estimated BAC to a limit you enter yourself.

Remember that the only truly safe BAC for driving or operating dangerous equipment is 0.00. When in doubt, do not drive. Explore more tools on MyTimeCalculator for finance, fitness, health, math, and science calculations.

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