Understanding the blood alcohol content calculator
Produce a simplified educational BAC estimate from weight, standard drinks, elapsed time, and a selected distribution factor.
This page provides an equation-based estimate for education and planning. It does not diagnose a condition, measure an individual response, or replace professional care.
How to use this health calculator
- Choose appropriate inputs: Enter measurements using the units and ranges shown.
- Review the assumptions: Confirm that the model applies before interpreting the result.
- Calculate and interpret: Read the result together with its limitations and cautions.
- Use professional guidance when needed: Do not use a general calculator to change medication, treatment, or a clinician-directed plan.
Formula and variables
The output follows the stated arithmetic and assumptions; it is not an individualized diagnosis, prognosis, or treatment recommendation.
Estimated BAC (%) = alcohol grams ÷ (body weight grams × distribution factor) × 100 − 0.015 × hours.- A — Alcohol
- U.S. standard drinks multiplied by 14 grams.
Worked example
A 70 kg adult enters two standard drinks over two hours using factor 0.68.
- Alcohol
- 28 g
- Weight and time
- 70 kg, 2 hours
- 28 ÷ (70,000 × 0.68) × 100 − 0.030 ≈ 0.029%
Result: The simplified estimate is about 0.029%.
Interpret the result with its population, measurement, and clinical limitations.
Understanding your results
Equation result
The numerical output follows the displayed formula and entered assumptions.
Personal interpretation
Individual biology, measurement error, environment, health conditions and medicines can change real-world outcomes.
Assumptions
- Inputs are accurate and use the displayed definitions and units.
- The cited reference or equation applies to the intended educational comparison.
Limitations
- Actual absorption and elimination vary substantially.
- Drink pours may contain more than one standard drink.
- BAC may continue rising after the last drink.
Common mistakes
- Using the result to decide whether to drive.
- Assuming a zero estimate proves sobriety.
Practical use cases
Educational estimate
Explore how the inputs affect the equation result.
Consistent tracking
Compare estimates only when methods, units and conditions are consistent.
Planning and decision guide
Treat cautions as part of the result
Never drive after drinking; use a sober ride. Call emergency services for signs of alcohol poisoning.
Escalate symptoms or clinical questions
Seek qualified medical advice for symptoms, diagnosed conditions, medicines, pregnancy, or individualized treatment decisions.
Frequently asked questions
Is this result individualized medical advice?
No. It is an educational calculation based on the displayed assumptions.
Can I use it to change treatment?
No. Treatment decisions require appropriate professional assessment.
Sources and review
- What Is a Standard Drink? — National Institute on Alcohol Abuse and Alcoholism. Accessed 2026-08-03.
Reviewed 2026-08-03.