Start with pure alcohol
Serving size × ABV × ethanol density tells you how much pure alcohol a drink contains. What does ABV mean? →
ALCOHOL INFORMATION TOOLS
BAC Calculator.
Clear limits. Safer planning.
Estimate blood alcohol concentration from your drinks, body weight, and elapsed time. Every result explains its limits—an estimate is never a decision to drive.
Start your BAC calculationCORE TOOL
BAC Calculator: estimate blood alcohol concentration
Estimate blood alcohol concentration from the drinks you actually had—not a blank “amount of alcohol” field.
MORE USEFUL TOOLS
Start with the number you know
Standard drinks & alcohol units
Convert any serving and ABV into the units used where you live.
Open calculator →Alcohol calories
See alcohol-only calories alongside pure alcohol and standard drinks.
Calculate calories →Standard drinks per container
Check the alcohol in a full bottle, can, pint, or other container.
Calculate a container →BAC estimate over time
See how a Widmark-style estimate changes across future hours.
See the estimate →BAC unit conversion
Convert a BAC percentage into g/dL, mg/dL, g/L, and mg per 100 mL.
Convert BAC units →Australia standard drinks
Use Australia’s 10 g standard-drink reference and read common labels.
Read the Australia guide →ABV to proof
Convert US-style proof and alcohol by volume from the label.
Convert ABV and proof →Alcohol grams
Find pure alcohol grams, reference units, and alcohol-only calories.
Calculate grams →Cocktail alcohol
Add up to three alcoholic ingredients in a cocktail recipe.
Calculate a cocktail →UK alcohol units
Calculate units from a product's volume and ABV.
Calculate UK units →Australia calculator
Calculate Australian standard drinks directly from label details.
Calculate Australian drinks →Party drink checklist
Build an inclusive beverage checklist with water and alcohol-free options.
Plan an event →KNOW THE BASICS
A drink is not always one standard drink.
Units change by country
One U.S. standard drink contains 14 g of pure alcohol. The UK and Australia use different definitions. See the country guide →
Time is the only reducer
Coffee, water, food, and cold showers may change how you feel, but they do not reliably lower BAC faster. What is BAC? →
Check the full bottle
Wine strength changes the total alcohol in a bottle. Wine bottle examples →
Beer is not one fixed amount
Container size and ABV both change the answer. Beer examples →
Know the limits of BAC estimates
A BAC tool estimates; it cannot measure or clear someone to drive. BAC levels explained →
Compare countries
The same alcohol amount produces different reference units around the world. Compare country units →
CLEAR ANSWERS
Before you rely on a number.
Can a blood alcohol calculator tell me whether I can drive?
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.
Why does this blood alcohol calculator show a range?
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.
Is a 12 fl oz beer always one standard drink?
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.
What is the difference between a standard drink and a serving?
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
A calculator should show its work.
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.
Read the method and limits