A tool to estimate your Blood Alcohol Content (BAC), which is the percentage of alcohol in your bloodstream.

It uses your input (like weight, sex, drinks consumed, and time spent drinking) in a formula, often the Widmark formula, to estimate your BAC.

BAC calculators provide an estimate only and are not 100% accurate. They can be off by up to 20% due to individual factors.

No. Never rely on a BAC calculator to decide if you are fit to drive. Any alcohol can impair driving ability.

It typically uses your body weight, biological sex, amount of alcohol consumed (in standard drinks), and the time over which you drank.

This varies greatly based on your weight, sex, metabolism, and the type of drink. A calculator uses standard drink sizes for its estimate.

The exact number of drinks varies based on the alcohol content, serving size, your body weight, sex, and drinking pace.

To convert a serum ethanol level in $\text{mg/dL}$ to $\text{BAC}$, move the decimal point three places to the left (e.g., $100\text{ mg/dL}$ is $\text{0.10\% BAC}$).

No single online calculator is definitively “best”; they all provide estimates. Look for one that includes more factors like food consumption for a better approximation.

You should only drive when your BAC is $\text{0.00\%}$ or you have consumed no alcohol. Do not drive if you have had any drinks.

The calculator will estimate the time until your BAC returns to $\text{0.00\%}$, but this is only an approximation. Time is the only thing that lowers $\text{BAC}$.

They are approximate tools for educational use. Actual $\text{BAC}$ is affected by many factors (food, medication, health) not fully accounted for.