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BAC Calculator

Use Alcomato's free BAC calculator to estimate your blood alcohol content. Enter your body profile, what you drank, and your drinking timeline to get an accurate estimate based on the Widmark formula with Watson TBW correction.

Your Profile

⚫ Sex
⚖ Weight
lbs
154 lbs
┃ Height
ft in
5' 7"
📅 Age
years
↑ Alcohol Tolerance

Drinking Timeframe

🕑 Start time
📅 End time

Food Intake

How much did you eat before/while drinking?

☕
Empty
Barely ate
🍴
Little
Snacks only
🍕
Normal
Regular meal
🥣
A Lot
Full meal
Food slows alcohol absorption and can reduce peak BAC by up to 30%

What did you drink?

Your Results

MINIMAL
0.00‰
Current Blood Alcohol

This is an estimate only. Do not drive or operate machinery if you have consumed alcohol. Individual metabolism varies significantly.

↑ Peak Permille
0.00 ‰
🕐 Estimated Sober
Now
Based on average metabolism rate
Hour-by-Hour Breakdown

What is Blood Alcohol Content (BAC)?

Blood Alcohol Content (BAC) is a measurement of the amount of alcohol present in your bloodstream, expressed as a percentage of alcohol per volume of blood. For example, a BAC of 0.08% means there are 0.08 grams of alcohol per 100 milliliters of blood. In many countries, BAC is also expressed in permille, where 0.8 permille equals 0.08%. BAC is influenced by factors such as body weight, sex, the amount and type of alcohol consumed, the rate of consumption, and whether food was eaten.

How is BAC Calculated?

Our calculator uses the Widmark formula enhanced with the Watson Total Body Water (TBW) correction. This method calculates your total body water based on your sex, weight, height, and age, then determines how alcohol distributes through your body. The formula accounts for alcohol absorption rate, metabolism rate (typically 0.15 permille per hour), food intake which slows absorption, and individual tolerance levels that affect metabolism speed.

Legal BAC Limits by Country

Important Disclaimer

This calculator provides estimates only and should never be used to determine whether you are safe to drive or operate machinery. Actual blood alcohol levels vary significantly between individuals due to differences in metabolism, medications, health conditions, and other factors. If you have consumed any amount of alcohol, do not drive.

Frequently Asked Questions

How accurate is this calculator?

Alcomato uses a medically-informed simulation model (Widmark formula with Watson TBW correction) that accounts for your sex, weight, height, age, and tolerance. However, individual metabolism varies significantly — treat results as estimates only.

What is BAC / Permille?

BAC (Blood Alcohol Concentration) measures the amount of alcohol in your bloodstream. It can be expressed as a percentage (BAC %) or in permille (‰). 0.08% BAC equals 0.8‰ permille.

Does food really affect BAC?

Yes. Eating before or while drinking slows alcohol absorption from the stomach into the bloodstream. A full meal can reduce your peak BAC by up to 30% compared to drinking on an empty stomach.

Can I use this to decide if I'm safe to drive?

No. This calculator provides estimates only. Many factors affect your actual BAC including medications, hydration, and health conditions. If you have consumed any alcohol, do not drive.

What does tolerance level mean?

Tolerance affects your alcohol metabolism rate. Regular drinkers metabolize alcohol faster due to increased liver enzyme activity. Choose "Low" if you rarely drink, "High" if you drink frequently.

How long does alcohol stay in your system?

Alcohol is typically metabolized at a rate of about 0.15‰ per hour, but this varies based on weight, sex, liver health, and drinking frequency. Even after you feel sober, trace amounts may remain detectable in breath, blood, or urine for hours longer.