SafeBAC CalculatorInformational BAC Tool

Blood Alcohol Concentration (BAC) Calculator

Estimate your blood alcohol concentration (BAC) based on what you drank, your body weight, and time. See clear safety warnings and why you should never drive after drinking.

Estimate your BAC

Enter your details and drinks to see an approximate blood alcohol concentration. Results are only estimates and must not be used to decide if you can drive.

Use an approximate value if you are not sure. The estimate is sensitive to body weight.

This helps us compare your estimated BAC with commonly cited legal limits in your selected region.

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minutes

Count from the first sip of your first drink. The longer you have been drinking, the lower your BAC may be from metabolism.

Drinks you have consumed

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Never use BAC estimates to decide whether you can drive.

Estimated BAC and safety overview

These numbers are only rough estimates. Everyone processes alcohol differently.

Fill in your details and drinks, then select “Estimate BAC” to see estimated values and safety guidance.

What Is Blood Alcohol Concentration (BAC)?

Blood alcohol concentration (BAC) is the amount of alcohol in your bloodstream, usually expressed as a percentage. Even small increases in BAC can slow reaction time, reduce judgment, and make driving dangerous.

How to Use This BAC Calculator

  1. Select your sex, enter your body weight, and choose your country or region.
  2. Add the drinks you have consumed and when you started drinking.
  3. Click the "Estimate BAC" button to see your approximate level, legal risk, and an estimate of how long it may take to reach zero.

How This BAC Calculator Works

This calculator uses standard BAC estimation formulas that consider your sex, body weight, amount of alcohol consumed, and time since your first drink. The result is only an estimate because alcohol affects everyone differently.

Limitations and Accuracy

No online calculator can know your exact BAC. Metabolism, health conditions, food, medications, and many other factors can make your real BAC higher or lower than the estimate shown here.

Different countries and regions set different legal BAC limits for drivers. Many places also have stricter limits for new or professional drivers. Always check the rules where you live.

Effects at Different BAC Levels

As BAC rises, judgment, coordination, and reaction time decline. Even before you reach the legal limit you may be too impaired to drive safely.

Safety First

If you have been drinking, the safest choice is always not to drive. Choose a taxi, rideshare, public transport, or a sober driver instead of risking your life and others.

Explore related BAC tools

BAC Calculator FAQ

All online BAC calculators provide estimates only. This tool uses commonly accepted formulas and reasonable assumptions, but your actual BAC can be higher or lower based on metabolism, health, medications, and many other factors.
No. You should never use any BAC calculator to decide whether it is safe or legal to drive. If you have been drinking, the safest choice is always not to drive.
You will enter your sex, body weight, when you started drinking, and what types and amounts of alcoholic drinks you had. The calculator uses this to estimate how much alcohol is in your bloodstream over time.
No. All calculations run in your browser, and we do not store or send your drink details to our servers. You can clear or change your entries at any time.
Because of differences in body composition and how alcohol is distributed in the body, women typically reach a higher BAC than men after drinking the same amount of alcohol, even at the same body weight.
BAC time to zero is an estimate of how long it may take for your body to process alcohol and for your BAC to return to zero. Even when an estimate suggests you might be back at 0.00%, you can still feel the effects of alcohol.

Check Your Estimated BAC Before You Drive

Estimate your BAC, understand your legal risk, and choose a safer way home instead of driving after drinking.

Estimate My BAC