About BAC Calculator

Science-based blood alcohol education for responsible decision-making

Our Mission

BAC Calculator was created with a singular purpose: to provide accurate, science-based blood alcohol concentration education to help people make informed, responsible decisions about alcohol consumption.

We believe that knowledge is the foundation of safety. By understanding how alcohol affects the body and how BAC is calculated, individuals can better recognize impairment and make safer choices—especially when it comes to driving.

Our Core Values

  • Accuracy First: We use scientifically validated formulas, not guesswork
  • Education Over Judgment: Our tool is designed to inform, not to enable unsafe behavior
  • Privacy & Transparency: No data collection, no tracking—your information stays private
  • Safety Above All: We consistently emphasize that 0.00% BAC is the only safe level for driving

Scientific Foundation

Our BAC calculator is built on the Widmark formula, a scientifically validated method developed by Swedish physician Erik Widmark in the 1930s. This formula remains the gold standard for estimating blood alcohol concentration and is widely used in forensic toxicology, medical research, and legal proceedings.

The Widmark Formula

The formula accounts for four critical factors that determine your BAC:

  • Amount of Alcohol Consumed: Measured in standard drinks (1 drink = 14 grams of pure alcohol)
  • Body Weight: Heavier individuals have more blood volume, diluting alcohol concentration
  • Biological Sex: Women typically have lower water content (55% vs 68% in men), leading to higher BAC from the same alcohol amount
  • Time Elapsed: The body metabolizes alcohol at approximately 0.015% BAC per hour

Trusted Data Sources

All BAC level effects and safety information are based on research from:

  • NHTSA (National Highway Traffic Safety Administration) - Federal agency responsible for traffic safety
  • CDC (Centers for Disease Control and Prevention) - Leading public health institution
  • Medical Research: Peer-reviewed studies on alcohol metabolism and impairment

Accuracy Commitment

While our calculator provides estimates based on scientifically validated formulas, individual metabolism varies significantly. For legal or medical purposes, always rely on professional testing methods like breathalyzers or blood tests administered by qualified personnel.

What We Offer

BAC Calculator

Estimate your blood alcohol concentration based on gender, weight, number of drinks, and time elapsed. Get instant results with clear explanations of what your BAC means.

AI Assistant

Get personalized explanations about your BAC level, convert mixed drinks to standard drink units, and understand how long alcohol stays in your system.

BAC Effects Chart

Comprehensive guide to 6 BAC levels from 0.02% to 0.15%+, including typical effects, driving impairment, and legal consequences.

Privacy First

All calculations happen locally in your browser. We don't collect, store, or track any personal data. No accounts required, completely anonymous.

100% Free & Accessible

No registration, no hidden fees, no paywalls. Our mission is education and safety, not profit. BAC Calculator will always remain free for everyone.

Important Disclaimers

While we strive for accuracy, it's crucial to understand the limitations of any BAC calculator:

⚠️ NOT for Determining Driving Safety

The only safe BAC for driving is 0.00%. Never use this tool to determine if you're safe to drive. Even small amounts of alcohol impair judgment, reaction time, and coordination. Impairment begins at BAC levels as low as 0.02%. If you've been drinking, use alternative transportation—call a rideshare, taxi, or designated driver.

📚 Educational Purpose Only

This tool is designed for educational purposes to help you understand how alcohol affects the body. It does NOT constitute medical advice, legal advice, or professional consultation. Do not rely on these estimates for any legal, medical, or employment-related decisions.

🔬 Individual Variation

Alcohol metabolism rates vary by 20-30% between individuals based on age, liver health, genetics, medications, food intake, and other factors. Our calculator provides general estimates—your actual BAC may be higher or lower.

🚫 No Guarantees

We make no warranties about the accuracy, completeness, or reliability of BAC estimates. Use this information at your own risk. The developers and operators of this site assume no liability for decisions made based on information provided by this tool.

Contact & Support

We're committed to continuous improvement and value your feedback. If you have questions, suggestions, or encounter any issues, please don't hesitate to reach out.

Get in Touch

You can also explore our other resources:

Remember: The safest choice is always to plan ahead. If you're going to drink, arrange for a designated driver, rideshare, or other safe transportation before you start. Your safety and the safety of others is paramount.