BAC Calculator

Our BAC calculator uses the Widmark formula to estimate your blood alcohol content based on your body weight, biological sex, number and type of drinks consumed, and time since your first drink. It accounts for alcohol metabolism rate to show how your BAC changes over time and estimates when you'll be sober again. Remember: this is an estimate — actual BAC varies based on many factors including food intake, medications, and individual metabolism.

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New
lbs
0 hrs
hrs
12 hrs
Custom Drink Settings
Estimated BAC local_bar
0.000%
Sober
Time to Sober
Sober now
Peak BAC
0.000%
Standard Drinks
0
Alcohol Calories
0 cal
BAC Level
0.00 0.05 0.08 0.15 0.20+

warning Disclaimer: This is an estimate only. Actual BAC varies based on many factors. Never use this to decide if you're safe to drive.

lightbulb Tips

  • 1 standard drink = 12oz beer, 5oz wine, 1.5oz spirits
  • Body metabolizes ~1 drink per hour
  • 0.08% BAC = legal limit in most US states
  • Only time lowers BAC — not coffee or water

How to Use This Calculator

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Enter Your Details

Input your body weight and select biological sex. These determine how your body distributes alcohol.

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Add Your Drinks

Enter the number and type of drinks consumed. Use preset drink types or customize ABV and serving size.

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Set Time Elapsed

Enter how long since your first drink. This accounts for alcohol your body has already metabolized.

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Review BAC Results

See your estimated BAC, impairment level, legal status, and time until sober. Remember: this is an estimate only.

The Formula

The Widmark formula is the standard method for estimating BAC. It calculates alcohol concentration based on the total alcohol consumed relative to body water content (which differs by sex). The metabolism rate (0.015/hr average) represents how fast your liver processes alcohol over time.

BAC = (Alcohol in grams / (Body weight in grams × r)) × 100 - (0.015 × hours)

lightbulb Variables Explained

  • Alcohol (g) Total grams of pure alcohol consumed = drinks × oz × ABV × 29.5735 × 0.789
  • Body weight (g) Body weight converted to grams
  • r Widmark factor: 0.68 for males, 0.55 for females
  • 0.015 Average BAC metabolism rate per hour (range: 0.010-0.020)
  • hours Time elapsed since first drink

tips_and_updates Pro Tips

1

One 'standard drink' = 12 oz beer (5%), 5 oz wine (12%), or 1.5 oz spirits (40%)

2

Your body metabolizes about one standard drink per hour on average

3

Food slows alcohol absorption but doesn't prevent intoxication

4

BAC of 0.08% is the legal limit in most US states — but impairment starts well below that

5

Women generally reach higher BAC than men at the same weight due to lower body water content

6

Coffee, cold showers, and exercise do NOT lower your BAC — only time does

7

Medications can dramatically increase alcohol's effects even at low BAC levels

Calculate Your Blood Alcohol Content (BAC)

Our free BAC calculator estimates your blood alcohol content based on your weight, gender, number of drinks, and time elapsed. See your impairment level, legal driving status, and how long until you're completely sober.

Blood Alcohol Content Calculator

How high is your BAC after drinking? Use our blood alcohol content calculator to find out. Based on the Widmark formula, it accounts for your weight, biological sex, drink type, and time to give you an accurate estimate. Whether you had beer, wine, or spirits, our BAC calculator shows your current level and impairment status.

How Long Until Sober Calculator

Wondering how long until your BAC reaches 0.00%? Your liver metabolizes alcohol at approximately 0.015% per hour — about one standard drink per hour. Our sobriety calculator shows exactly how long it will take based on your current estimated BAC level, so you can plan ahead for when it's safe to drive.

BAC Calculator by Weight and Gender

Body weight and biological sex significantly affect BAC. A 120 lb woman will reach a much higher BAC than a 220 lb man after the same number of drinks. Our BAC calculator by weight uses sex-specific Widmark factors (0.68 male, 0.55 female) for more accurate results tailored to your body.

Frequently Asked Questions

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Data sourced from trusted institutions

All formulas verified against official standards.