How is BAC (Blood Alcohol Content) calculated?

BAC is calculated using the Widmark formula. It divides the grams of alcohol consumed by your body weight multiplied by a gender-specific constant (0.68 for men, 0.55 for women), then subtracts the alcohol metabolized over time at approximately 0.015% per hour.

What is the legal BAC limit for driving?

In most US states, the legal BAC limit for driving is 0.08%. Many countries use 0.05%. Commercial drivers and those under 21 often face stricter limits of 0.02% or 0.00%. Impairment can begin at much lower levels than the legal limit.

How long does it take to sober up after drinking?

The body metabolizes alcohol at approximately 0.015% BAC per hour. For example, if your BAC is 0.08%, it would take roughly 5-6 hours to return to 0.00%. Nothing can speed up this process — not coffee, cold showers, or exercise.

How many drinks does it take to reach 0.08% BAC?

This varies based on weight, gender, and drinking speed. Generally, for a 70kg (154lb) male, approximately 3-4 standard drinks consumed within one hour may bring BAC near 0.08%. Women typically reach higher BAC levels with fewer drinks due to body composition differences.

What is a standard drink?

A standard drink contains about 14 grams of pure alcohol. This equals approximately 355ml (12oz) of 5% beer, 150ml (5oz) of 12% wine, or 44ml (1.5oz) of 40% distilled spirits. Different countries may define standard drinks differently.

Is this BAC calculator accurate?

This calculator provides estimates based on the scientifically-accepted Widmark formula. However, actual BAC can vary due to individual factors like metabolism, food consumption, medications, liver health, and hydration. Only professional breathalyzers or blood tests can measure BAC precisely.

Does food affect BAC levels?

Yes, eating food before or while drinking slows alcohol absorption into the bloodstream, which can result in a lower peak BAC. However, food does not prevent intoxication — it only delays and reduces the peak. Fatty and protein-rich foods are most effective at slowing absorption.

Blood Alcohol Calculator

Calculate your estimated blood alcohol content (BAC) in real-time. Add your drinks, track your BAC level over time, and find out when you'll be sober. Free, private, and based on the Widmark formula. Need help? Find AA meetings and alcohol support resources.

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