What is BAC?

Blood Alcohol Content (BAC) measures the percentage of alcohol in your bloodstream. 0.08% means 0.08 grams of alcohol per 100ml of blood. India's legal driving limit is 0.03% (much stricter than US 0.08%). This calculator uses the Widmark formula — standard estimation method — based on weight, sex, drinks consumed, and time elapsed. IMPORTANT: estimate only, not for deciding to drive.

How to use

1. Enter weight in kg — Body weight affects alcohol distribution
2. Choose sex — Women: lower body water content = higher BAC
3. Enter standard drinks — 1 drink = 14g alcohol (1 beer, 1 wine, 1 shot)
4. Enter hours elapsed — Body metabolizes 0.015% BAC per hour

Formula

Widmark Formula:

BAC = (alcohol_grams / (weight_grams × r)) × 100 – (0.015 × hours)

Where r = 0.68 (male) or 0.55 (female) — body water fraction.

Standard drink = 14g pure alcohol.

Tips

• NEVER use to decide if you can drive — this is estimate only
• India: 0.03% legal limit. Zero tolerance recommended.
• Food slows alcohol absorption — eat before drinking
• Body metabolizes 0.015% BAC per hour (about 1 drink/hour)
• BAC peaks 30-90 minutes after last drink
• Hangover doesn't mean alcohol cleared — can still impair next morning

FAQs

What is one 'standard drink'?

In India / globally: 14g pure ethanol. Examples: 1 bottle beer (330ml @ 5%), 1 glass wine (150ml @ 12%), 1 shot spirits (45ml @ 40%).

Why are women affected differently?

Women have lower body water content (55% vs 68% in men). Same alcohol distributes in less water = higher concentration = higher BAC.

How long until BAC = 0?

Body removes 0.015% BAC per hour. From 0.06%, takes 4 hours to clear. From 0.12% (very drunk), takes 8 hours. Sleep doesn't speed it up.

India alcohol laws?

Driving: 0.03% legal limit (much stricter than 0.08% in US). Penalty: fine + jail + license suspension. Many states have stricter rules; some are dry states (Gujarat, Bihar).

Related

BMI Calculator · Water Intake Calculator · BMR Calculator