BAC Calculator

Calculated using standard mathematical and industry formulas.

Free online Bac Calculator calculator to monitor your health, fitness, and nutrition goals.

How to use this calculator?

1. Select your gender and unit system.
2. Enter the number of standard drinks consumed (1 drink = 12 oz beer, 5 oz wine, 1.5 oz 80-proof spirit).
3. Enter hours elapsed since starting drinking.
4. View estimated current BAC %, peak BAC, legal driving status (0.08% limit), and time until sober.

Formula & calculation method

Widmark BAC & Metabolism Formula

BAC = [(Drinks × 14g) ÷ (Weight(g) × r)] × 100 − (0.015 × Hours)

r = 0.68 (males), 0.55 (females). Weight in grams = Weight(kg) × 1000.

Step-by-step calculation example

Male 75 kg, 3 drinks over 2 hours → Peak BAC ≈ 0.082%, Current BAC ≈ 0.052%.

Key insights to remember

• One standard US drink contains approximately 14 grams of pure ethanol.
• The body metabolizes alcohol at a roughly constant average rate of 0.015% BAC per hour.
• Coffee, cold showers, or exercise do not speed up alcohol metabolism — only time reduces BAC.

How to interpret your results?

Estimated BAC

Calculated percentage of alcohol present in blood stream.

Sober Time

Estimated hours required for BAC to decay to 0.00%.

Frequently asked questions

What is a Bac Calculator?

A Bac Calculator evaluates physiological metrics to guide health, fitness, or nutrition plans.

How often should I recalculate?

Recalculate every 4 to 8 weeks to track meaningful body composition or health changes.

Is this calculation accurate for athletes?

Athletes with high muscle mass may require body-fat specific formulas like Katch-McArdle.

How can I improve my results?

Combine balanced nutrition, regular resistance training, adequate sleep, and hydration.

Are results confidential?

Yes, all calculations run 100% locally in your browser with zero data storage.

Should I consult a physician?

Always consult a certified medical professional before starting aggressive diets or training regimes.

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