BAC Calculator – Blood Alcohol Content
lb
0–30
0–24 hrs
Enter drinks → see 12-hour BAC table + graphs…
Widmark + Watson • 12-hour table • Dual charts • 0.015%/hr burn
BAC Calculator – Estimate Your Blood Alcohol Level Instantly
Have you ever wondered how alcohol affects your body — or when it’s safe to drive after drinking? The BAC Calculator (Blood Alcohol Content Calculator) on GCalculate.com helps you estimate how much alcohol is in your bloodstream based on your drinks consumed, body weight, gender, and time since drinking. This calculator provides a quick, reliable way to understand your estimated BAC level and its effects — helping you stay safe, aware, and within the legal limits.
What Is BAC (Blood Alcohol Content)?
BAC (Blood Alcohol Content) is the amount of alcohol present in your bloodstream, expressed as a percentage.
For example:
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A BAC of 0.08% means you have 0.08 grams of alcohol per 100 milliliters of blood.
In most countries, 0.08% is the legal limit for driving. Anything higher can impair judgment, coordination, and reaction time — and lead to legal penalties or accidents.
How the BAC Calculator Works
The BAC Calculator on GCalculate uses a scientific formula to estimate your current blood alcohol concentration based on four main factors:
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Number of drinks consumed
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Alcohol percentage (beer, wine, liquor, etc.)
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Body weight
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Time since last drink
The calculator uses the Widmark formula, a proven scientific method for estimating BAC:
BAC=(A×5.14)(W×r)−0.015×HBAC = \frac{(A \times 5.14)}{(W \times r)} – 0.015 \times H
Where:
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A = total alcohol consumed (in ounces)
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W = body weight (in pounds)
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r = alcohol distribution ratio (0.73 for men, 0.66 for women)
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H = hours since drinking began
This equation estimates your peak BAC and then subtracts metabolized alcohol over time (0.015 per hour, on average).
Common BAC Levels and Effects
| BAC Level | Typical Effects | Possible Consequences |
|---|---|---|
| 0.02–0.03% | Mild relaxation | Slight euphoria, reduced inhibition |
| 0.04–0.06% | Warmth, confidence | Impaired judgment, slower reaction |
| 0.07–0.09% | Euphoria, balance issues | Illegal to drive in most regions |
| 0.10–0.15% | Slurred speech | Poor coordination, risk of accident |
| 0.16–0.30% | Confusion, dizziness | Vomiting, loss of control |
| 0.30%+ | Dangerously high | Risk of unconsciousness or death |
Even small amounts of alcohol can affect your reaction time and focus — so it’s always best to avoid driving entirely after drinking.
FAQ
What does BAC mean?
BAC stands for Blood Alcohol Content, which measures the percentage of alcohol in your bloodstream. A BAC of 0.08% is the legal driving limit in most regions.
How is BAC calculated?
BAC is calculated using the Wid mark formula, which factors in your weight, gender, drinks consumed, and time since drinking began.
What is the legal BAC limit for driving?
In most countries and U.S. states, the legal limit is 0.08%. However, some places have lower limits, especially for commercial drivers or underage individuals.
How long does it take to sober up?
On average, your body metabolizes 0.015% BAC per hour, but this varies by person. Drinking water and resting help, but only time lowers BAC.
Can I use the BAC Calculator for legal purposes?
No. The calculator provides educational estimates only. For official or legal testing, use a professional breathalyzer or blood test.