Blood Alcohol Content Calculator

Estimate your BAC using the Widmark formula based on your weight, drinks, and time

Enter Your Details

Gender

Body Weight (kg)

Number of Drinks

Drink Size (ml)

Standard beer: 330ml, Wine glass: 150ml, Shot: 45ml

Alcohol Content (% ABV)

Beer: 4-6%, Wine: 12-15%, Spirits: 35-50%

Time Since First Drink (hours)

Your Estimated BAC

0.000%

Blood Alcohol Content

Estimated Time Until Sober:

You are sober

Important Disclaimer

This calculator provides estimates only. Actual BAC varies based on many factors including food consumption, metabolism, medications, and individual physiology.Never drive or operate machinery after drinking, regardless of calculated BAC. Legal limits vary by country (typically 0.05-0.08%). When in doubt, don't drive.

BAC Levels Reference

Sober

0.00 - 0.02%

No apparent effects, normal behavior

Mild Effects

0.02 - 0.05%

Relaxation, slight mood elevation, mild impairment

Impaired

0.05 - 0.08%

Reduced inhibitions, impaired judgment, slower reaction time

Legally Drunk

0.08 - 0.10%

Legal limit in most countries. Poor coordination, impaired balance

Significant Impairment

0.10 - 0.15%

Clear deterioration of motor control, slurred speech

Severe Impairment

0.15+%

Major loss of balance, vomiting possible, potential blackout

How It Works

This calculator uses the Widmark Formula, the standard method for estimating BAC:

BAC = (A / (r x W)) x 100 - (0.015 x h)

A = Alcohol consumed (grams)
r = Gender constant (0.68 male, 0.55 female)
W = Body weight (grams)
h = Hours since drinking started

Factors Affecting BAC

Food consumption (eating slows absorption)
Rate of drinking (faster = higher peak BAC)
Body composition (muscle vs fat)
Medications and health conditions
Tolerance level (affects feeling, not BAC)
Age and metabolism rate