288 free calculators - no signup required

CalcHive: Free Online Calculators for Finance, Health & More

288 professional tools for finance, health, freelancing, and creator analytics - delivering accurate answers instantly, with no account required.

Browse All 288 Tools

288+ Professional Tools0 Signups RequiredPrivacy-FirstUsed Worldwide

No Signup100% FreeInstant ResultsMobile ReadyTrusted Formulas

Popular right now

Mortgage CalculatorBMI CalculatorGPA CalculatorAge CalculatorScientific Calc

BAC Calculator – Blood Alcohol Content Estimate (Widmark Formula)

Blood alcohol content (BAC) is the concentration of alcohol in the bloodstream, expressed as a percentage. Even a single drink affects cognitive function and reaction time, and legal driving limits in most countries sit at 0.08% BAC or lower. Understanding how BAC relates to drinks consumed, body weight, and time helps people make more informed decisions.

This calculator estimates BAC using the Widmark formula, the most widely used scientific model for BAC estimation. Results are educational estimates only — actual BAC varies based on individual metabolism, food consumption, hydration, and other factors that no formula can fully capture.

How to use the Bac Calculator

Enter your sex (affects alcohol distribution ratio in the body).

Enter your body weight.

Enter the number of standard drinks consumed.

Enter the time elapsed since drinking started.

View estimated BAC and approximate effects at that level.

Estimated BAC Effects by Level
BAC Level	Approximate Effects
0.02–0.03%	Mild relaxation, slight mood elevation
0.04–0.06%	Reduced inhibition, slight impairment of judgement
0.07–0.09%	Noticeable impairment, reduced coordination — at/near legal limit
0.10–0.12%	Significant impairment of balance, speech, reaction time
0.13–0.15%	Severe impairment, potential nausea
0.16–0.19%	Dysphoria, disorientation
0.20%+	Risk of serious medical emergency

Bac Calculator FAQ

How accurate is the Widmark formula?

The Widmark formula gives a reasonable estimate but cannot account for individual variation in alcohol metabolism, liver function, food intake, medications, or hydration. It's an approximation for educational purposes, not a precise measurement.

How long does it take to sober up?

The liver processes alcohol at approximately 0.015% BAC per hour (roughly one standard drink per hour). Time is the only reliable way to reduce BAC — coffee, food, and exercise do not speed up the process.

What counts as a standard drink?

In the US: 14 grams of pure alcohol — equivalent to 12 oz of 5% beer, 5 oz of 12% wine, or 1.5 oz of 80-proof spirits. Craft beers with higher ABV count as more than one standard drink.

Does body weight affect BAC significantly?

Yes. A heavier person has more blood and body water to dilute the alcohol, resulting in lower BAC from the same amount of alcohol. This is why the Widmark formula includes body weight as a key variable.