Alcohol Units / BAC Rough Estimator (Educational Only)
Estimate approximate alcohol units and a very rough BAC using simple formulas. For educational awareness only. Not medical or legal advice. Never use this tool to decide if it is safe or legal to drive or operate anything.
Converts your drinks into approximate units / grams of alcohol. Uses a simple Widmark-style formula to estimate rough BAC over time. Not medical advice, legal advice, or personalized safety advice. BAC estimates can be very inaccurate for real people. Never use this to decide if you can drive, operate machinery, or do anything safety-critical.
Enter Your Information
kg
Used for generic Widmark factor only
Drinks *
Timing
Metabolism Rate
Context (For warnings only)
Enter your weight and drinks to see approximate alcohol units and a very rough BAC curve over time. This is educational only, not medical or legal advice. Never use this to decide if it is safe or legal to drive or operate anything.
What "Standard Drinks" / Units and Grams of Alcohol Mean
A "standard drink" or "unit" is a way to measure how much pure alcohol is in different types of alcoholic beverages. Different countries use different definitions, but the general idea is to help people understand how much alcohol they're consuming regardless of the type of drink.
This calculator uses an internal definition where 1 unit equals 14 grams of pure alcohol (similar to a US standard drink). This means that a 12-ounce beer at 5% ABV, a 5-ounce glass of wine at 12% ABV, and a 1.5-ounce shot of spirits at 40% ABV are all roughly equivalent in terms of pure alcohol content.
Note: This is a simplified educational definition. Actual standard drink definitions vary by country and organization. This tool is for awareness only, not for making safety or legal decisions.
Very High-Level Explanation of BAC
Blood Alcohol Concentration (BAC) is a measure of how much alcohol is in a person's bloodstream, typically expressed as a percentage. For example, a BAC of 0.08% means that 0.08% of a person's blood volume is alcohol.
BAC is influenced by many factors, including:
- The amount of alcohol consumed
- Body weight and composition
- Sex assigned at birth (affects body water percentage)
- How quickly alcohol is consumed
- Whether food was eaten
- Individual metabolism rates
- Medications and health conditions
This calculator uses a simplified Widmark-style formula to estimate BAC, but real BAC can vary significantly from these estimates.
Important: This tool provides very rough estimates only. Real BAC depends on many individual factors and cannot be accurately predicted by a simple calculator.
Why BAC Calculators Are Approximate and Not Reliable for Individuals
BAC calculators, including this one, use simplified formulas that cannot account for the many individual factors that affect how alcohol is absorbed, distributed, and eliminated from the body.
Factors that can cause real BAC to differ from estimates include:
- Individual metabolism: People metabolize alcohol at different rates based on genetics, liver function, and other factors.
- Food intake: Eating before or while drinking can slow alcohol absorption.
- Medications: Some medications can affect how alcohol is processed.
- Health conditions: Liver disease, diabetes, and other conditions can affect alcohol metabolism.
- Hydration: Dehydration can affect BAC.
- Timing: The rate at which drinks are consumed matters, not just the total amount.
Critical: This calculator cannot accurately predict your actual BAC. Law enforcement breathalyzers, medical blood tests, and other professional measurements will not match these estimates. Never use this tool to decide whether you are safe or legal to drive or do anything else.
Strong Safety Message: Never Rely on Calculators for Safety Decisions
This tool is designed for educational awareness only. It is not a medical device, legal tool, or safety instrument. It should never be used to make decisions about:
- Whether it is safe to drive
- Whether it is legal to drive
- Whether it is safe to operate machinery
- Whether it is safe to supervise children
- Whether it is safe to swim or engage in water activities
- Any other safety-critical activity
If you have consumed alcohol and are considering any activity that requires alertness, coordination, or judgment, the safest approach is to:
- Wait until you are completely sober
- Arrange safe transportation (designated driver, rideshare, taxi, public transit)
- Not engage in the activity if there is any doubt about your ability to do it safely
Never use any BAC calculator to decide whether to drive or do anything dangerous. If there is any possibility you are impaired, do not drive and arrange safe transportation instead.
Seeking Professional Help If Struggling with Alcohol Use or Safety
If you are concerned about your alcohol use, have a history of alcohol-related issues, or want to cut down or quit, professional support can help. Healthcare professionals, therapists, support groups, and helplines can provide guidance, resources, and ongoing support tailored to your situation.
This calculator only provides rough estimates of alcohol units and BAC. It cannot provide medical advice, treatment recommendations, or personalized support. For health concerns, quitting strategies, or support, always consult with qualified professionals.
Remember: This tool is for educational purposes only. It is not medical, therapeutic, or counseling advice. For health questions, quitting strategies, or support, always consult with healthcare professionals or evidence-based support services.
Frequently Asked Questions
Common questions about using this BAC estimator and alcohol awareness.
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