BAC Calculator
Estimate blood alcohol concentration from drinks, body weight and time.
Enter your values to see the result.
An estimate for education only. Never use a calculator to decide whether it is safe to drive.
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- Daily Calorie Calculator — See your daily calorie needs.
- Hours Calculator — Count the hours since a time.
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Clear instructions
Find steps, examples and limitations below.
Use online
Open the tool in a supported web browser.
Free to use
No sign-up required. Tool-specific limits may apply.
How to use the BAC Calculator
Estimate blood alcohol concentration from drinks, body weight and time.
- 1 Enter your sex and body weight.
- 2 Enter how many beers, glasses of wine and shots you drank.
- 3 Enter the hours since your first drink and read the estimate.
Example and practical tips
Two beers and a glass of wine over two hours for a 75 kg man gives an estimate of about 0.04%. Never use an estimate to decide whether to drive.
Frequently asked questions
How fast does alcohol leave the body?
Roughly 0.015% BAC per hour on average; nothing speeds this up, including coffee or water.
Is it safe to drive under the limit?
Any alcohol impairs driving. The only safe choice is not to drink and drive.
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Something broken or not quite right? Tell us and we will look into it.