BAC Calculator | Blood Alcohol Calculator & Estimate

ALCOHOL INFORMATION TOOLS
Use this educational blood alcohol calculator to estimate BAC from your drinks, body weight, and elapsed time. Every result explains its limits—an estimate is never a decision to drive.
If you’ve been drinking, arrange a sober ride or wait until you are fully sober.
Estimate blood alcohol concentration from the drinks you actually had—not a blank “amount of alcohol” field.
Choose a starting point, then adjust the serving or ABV if needed.
Educational estimate only. Calculation happens in your browser; we do not save the values you enter.
Your result will show total alcohol, a BAC range, and the assumptions behind it.
Absorption, food, medication, health, serving size, and individual metabolism can change a real BAC. Only a properly used breath or blood test can measure it.
Continue with the question you have
Plan the safer next step. Do not drive, cycle, operate machinery, or rely on this estimate for a legal or medical decision.
Share the educational tool — never a personal result.
Convert any serving and ABV into the units used where you live.
See alcohol-only calories alongside pure alcohol and standard drinks.
Check the alcohol in a full bottle, can, pint, or other container.
See how a Widmark-style BAC estimate changes across future hours.
Explore a model timeline and why an online BAC estimate is never a measurement.
Convert a BAC percentage into g/dL, mg/dL, g/L, and mg per 100 mL.
Use Australia’s 10 g standard-drink reference and read common labels.
Convert US-style proof and alcohol by volume from the label.
Find pure alcohol grams, reference units, and alcohol-only calories.
Add up to three alcoholic ingredients in a cocktail recipe.
Compare two labels by container size, ABV, pure alcohol and local reference units.
Calculate units from a product's volume and ABV.
Use the U.S. 14 g reference and calculate from a product label.
Build an inclusive beverage checklist with water and alcohol-free options.
Use your own purchase assumptions to view weekly, monthly and annual spending.
Serving size × ABV × ethanol density tells you how much pure alcohol a drink contains. What does ABV mean? →
One U.S. standard drink contains 14 g of pure alcohol. The UK and Australia use different definitions. See the country guide →
Coffee, water, food, and cold showers may change how you feel, but they do not reliably lower BAC faster. What is BAC? →
Wine strength changes the total alcohol in a bottle. Wine bottle examples →
Container size and ABV both change the answer. Beer examples →
A BAC tool estimates; it cannot measure or clear someone to drive. BAC levels explained →
The same alcohol amount produces different reference units around the world. Compare country units →
No. This is an educational estimate, not a breath test or a legal or medical assessment. The NHTSA explains that it is difficult to assess your own BAC or impairment. If you have been drinking, arrange a sober ride instead. Learn what BAC means.
Food, timing, drink size, body composition, health conditions, medication, absorption, and individual metabolism can all change actual BAC. A breath or blood test is needed to measure it. See our assumptions and limits.
An online BAC calculator can show the arithmetic of an estimate, but it cannot accurately determine an individual's actual BAC. It cannot know every drink's timing, absorption, health context, medication, or metabolism. Treat the result as educational context, not a breath test, legal opinion, or reason to drive. Learn how BAC is measured.
No. Alcohol amount depends on serving size and ABV. A 12 fl oz beer at 5% ABV is about one U.S. standard drink, while a stronger beer can contain more. See country definitions and examples.
A serving is the amount poured or sold. A standard drink is a country-specific reference amount of pure alcohol, so one serving can contain less than, equal to, or more than one standard drink.
TRANSPARENT BY DESIGN
Our BAC estimate uses a Widmark-style calculation based on total pure alcohol, body weight, sex used in the formula, and elapsed time. We show a range because a person’s real BAC cannot be accurately determined from an online form.