About

Blood Alcohol Concentration (BAC) Calculator is an online tool that estimates the concentration of alcohol in your body and shows how long it will take to sober up. However, keep in mind that the results are only approximate and this alcohol calculator can in no way be evidence of sobriety.

Our goal is to become the go-to resource for everything related to alcohol—from understanding its effects on the body to knowing the legal alcohol driving limits in different countries.

We strive to provide accurate and reliable information to help people make informed decisions about alcohol consumption and responsible driving.

A key part of our mission is our BAC Calculator, a tool designed to estimate your blood alcohol concentration (BAC) and give an approximate time for sobering up based on your drinking habits. While the results are estimates, they serve as a valuable guideline for understanding how alcohol affects your body.

By offering both informational resources and practical tools, we aim to promote awareness, safety, and responsible alcohol consumption worldwide.

This tool estimates your blood alcohol concentration (BAC) with the Widmark formula, the method forensic toxicologists have used since 1932:

BAC = (A ÷ (r × W)) − (β × t)

• A — grams of pure alcohol you drank. In Spain a standard drink (UBE) is about 10 g (this figure varies by country).
• r — the Widmark distribution factor, the share of your body made up of water: roughly 0.68 for men and 0.55 for women.
• W — your body weight.
• β — how fast your body clears alcohol, on average 0.015 g/100 ml per hour (adjustable in the calculator).
• t — hours since your first drink.

Each drink is counted as fully absorbed the moment you have it. In reality the level keeps rising for roughly 30–90 minutes after a drink, so the peak shown is usually higher than the real one and early readings are deliberately on the high side.

If you set a time for each drink, the calculator adds each one at the moment you had it and removes β per hour from the running total (never below zero), so a later drink can raise the level again.

Because elimination is close to linear, the same formula estimates how long until your BAC returns to zero. The output is an estimate only: stomach contents, medication, hydration, health and individual metabolism all change the real figure, so it can never serve as proof of sobriety.

Sources: Posey & Mozayani, “The estimation of blood alcohol concentration: Widmark revisited” (2007); E. M. P. Widmark (1932); NHTSA.

The Blood Alcohol Concentration (BAC) Calculator on bacalculator.com/es/en is an online tool designed to estimate your BAC level and provide an approximate time for sobering up. This tool is for informational purposes only and should not be used as a substitute for professional medical, legal, or safety advice.

Results may vary based on individual metabolism, health conditions, alcohol tolerance, and other factors such as food consumption and hydration levels. The calculator does not take into account variations in body composition, medical conditions, or interactions with medications that may affect alcohol processing. We do not guarantee the accuracy, reliability, or real-world applicability of the estimates provided. The figures generated should be considered general guidelines rather than precise calculations.

Always make responsible decisions regarding alcohol consumption. Never operate a vehicle, heavy machinery, or engage in activities requiring full cognitive function after drinking. For legal or health-related concerns, consult a qualified professional.

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2. Use of the BAC Calculator This website provides an estimate of Blood Alcohol Concentration (BAC) based on user input, including weight, gender, and type of alcohol consumed. The calculations are approximate and should not be relied upon for legal, medical, or safety decisions. Individual variations can cause actual BAC levels to differ significantly from the estimates provided.
3. No Liability We are not responsible for any actions taken based on the results provided by this website. The use of this site is entirely at your own risk. We disclaim any liability for damages, injuries, legal consequences, or losses resulting from reliance on the BAC estimates.
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