About SafeBAC Calculator
Learn why this BAC calculator was created, how it estimates blood alcohol concentration, and how you should use it safely.
Our mission
SafeBAC Calculator exists to help people better understand how alcohol can affect their ability to drive safely and make decisions. Online information about BAC is often scattered, overly technical, or presented without clear safety context. We aim to offer a simple, honest tool that always points users toward safer choices.
How this calculator works
The BAC estimates are based on widely used Widmark-style formulas. These formulas combine information about your sex, body weight, the volume and strength of drinks consumed, and the time since your first drink. They estimate how much alcohol might be in the water in your body and subtract a typical elimination rate per hour.
Important limitations
Even with detailed inputs, formulas cannot know your exact blood alcohol concentration. Metabolism can vary with genetics, liver health, medications, food, hormones, sleep, and many other factors. Two people who drink the same amount may have very different BAC levels. For this reason, all values shown on this site must be treated as rough estimates only.
How you should use this site
Use SafeBAC Calculator as an educational tool to understand risk, not as a decision engine. Higher estimates should be viewed as warnings. Lower estimates should never be treated as proof that you are safe or legal to drive. If you have been drinking, the safest choice is always to avoid driving yourself and find another way home.
Medical and legal review
We plan to collaborate with medical and legal professionals to review the formulas, explanations, and safety messaging on this site. When formal reviewers are added, their credentials and the dates of review will be listed here so that you can see who has helped check the information.
Content updates
Alcohol research and traffic laws change over time. We periodically review the content and references on this site and update them as needed. If you believe something is outdated or inaccurate, please use the contact details in the disclaimer and privacy policy to let us know.
Key reference sources
SafeBAC Calculator is informed by public health resources and educational materials from trusted organizations, including:
- National and regional health agencies that publish guidance on alcohol and driving.
- Government traffic safety and licensing authorities that describe drink-driving limits.
- Educational and clinical summaries that explain Widmark-style BAC formulas and their limitations.