Blood Alcohol Content (BAC) Calculator

Typical range ~0.010–0.020; default 0.015.
If you use the drink builder below, its total will override this value.
Type
Size
Unit
ABV % ⓘ
Standard drinks ⓘ
Builder total: 0.00 standard drinks
Field meanings: Type = kind of drink · Size = volume · Unit = measurement unit (mL or fl oz) · ABV % = alcohol by volume (e.g. beer 5, wine 12, spirits 40) · Standard drinks = number of “standard drinks” in that row (US 14 g alcohol / UK 8 g / AU 10 g — adjusted by Region selector).
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About Blood Alcohol Content (BAC) Calculator

This Blood Alcohol Content (BAC) Calculator estimates your BAC based on drink quantity, strength, body weight, sex, and time since drinking. It uses a Widmark-style formula commonly applied in forensic and medical contexts. Results are educational estimates only—real values can vary due to absorption rates, medications, food, and individual metabolism. Always drink responsibly and never rely on online tools to decide if you can drive.

FAQ

  • What is a standard drink? In the U.S., one standard drink contains about 14 grams of pure alcohol — roughly equal to 12 oz of beer (5%), 5 oz of wine (12%), or 1.5 oz of spirits (40%). Note that actual serving sizes and alcohol by volume (ABV) can vary.
  • Why is the β (beta) elimination rate adjustable? Because alcohol metabolism differs among individuals. The typical rate of 0.015 g/dL per hour is an average teaching value, but factors like sex, age, body composition, and liver health can alter it significantly.
  • What affects my BAC level? Your BAC depends on number of drinks, alcohol strength, body weight, biological sex, and drinking duration. Food intake can also slow alcohol absorption and reduce peak BAC.
  • What are common legal BAC limits? Most regions set 0.08% (0.08 g/dL) as the legal driving limit for adults, though lower thresholds apply in some countries and for commercial or novice drivers.
  • Can this calculator determine if I can drive? No. This tool provides an estimate only. Your actual BAC may differ. Never rely solely on online estimates—use a certified breathalyzer and always arrange safe, sober transportation.

Disclaimer

For informational purposes only — no guarantees of accuracy. Do not drink and drive. Only approved testing determines legal impairment.

References

  • Widmark, E. M. P. (1932). Principles and Applications of Medicolegal Alcohol Determination. Biomedical Publications, 1981 reprint.
  • National Highway Traffic Safety Administration (NHTSA). Alcohol and Highway Safety: A Review of the State of Knowledge. DOT HS 811 374, 2011.
  • Centers for Disease Control and Prevention (CDC). Fact Sheets – Alcohol Use and Your Health. Available at: cdc.gov/alcohol
  • World Health Organization (WHO). Global status report on alcohol and health 2018. Geneva: WHO.
  • U.S. Department of Transportation. Drinking & Driving Laws and BAC Limits by Country. Available at: transportation.gov