Blood Alcohol Guides

How blood alcohol is estimated, how long it takes to leave, and what the legal limits mean

These guides explain the science behind the estimate, why it is shown as a range, and how to read the time until zero and the drink-drive limits. None of them can tell you that driving is safe — that is never a number a calculator can give.

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Complete Guide

What BAC is, how it is estimated, why it comes as a range, and how long alcohol takes to leave the body

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Quick Guides

Using the estimate

How long until you are sober

Reading the time-to-zero, hour by hour, and why only time removes alcohol

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Drink-drive limits, country by country

What the standard, novice, and professional limits mean, and why "under the limit" is not "safe to drive"

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Try your own estimate

Enter your drinks, body data, and country to see the estimate as a range, the time until zero, and the local limits.

Open the BAC Calculator