🍶 BAC Calculator (Blood Alcohol Content)

Estimate your Blood Alcohol Content (BAC) using the Widmark formula from your gender, body weight, drinks consumed, and hours elapsed. This is a rough reference estimate only and may differ from your actual BAC.

Gender

Male Female

Body Weight (kg)

Hours Since Drinking Started (hours)

Drinks Consumed (enter number of glasses)

Soju (1 glass, 50ml, 17% ABV)

Beer (1 glass, 200ml, 5% ABV)

Wine (1 glass, 150ml, 12% ABV)

Whiskey (1 shot, 30ml, 40% ABV)

Estimated Blood Alcohol Content (BAC)

0.000%

Total Alcohol Consumed: 0 g

Compare Against Legal Driving Limits by Country

⚠️ Please Read Before Using

This calculator is a rough estimate only, based on simplified averages (the Widmark formula). Your actual BAC can vary significantly depending on individual metabolism, food intake, medication, and health condition. This result must NEVER be used to decide whether it is safe to drive, and it has no legal or medical validity whatsoever. Your actual BAC must be verified with a breathalyzer or blood test.

GUIDE

Learn more

What Is the Widmark Formula?

The Widmark formula, published in 1932 by Swedish scientist Erik Widmark, estimates blood alcohol content by approximating how alcohol distributes through body water using a distribution constant (r).

BAC(%) = (alcohol consumed (g) ÷ (body weight (g) × r)) × 100 − (0.015 × hours elapsed)

The distribution constant r is typically about 0.68 for men and 0.55 for women (women tend to have a lower proportion of body water due to higher average body fat percentage). Alcohol is assumed to be eliminated at roughly 0.015%/hour. This formula is a simplified population-average estimate — actual metabolism varies significantly between individuals.

Grams of Alcohol Per Standard Drink

Grams of alcohol = volume (ml) × (ABV ÷ 100) × 0.789 (density of ethanol).

Drink	Standard Serving	ABV	Alcohol (g)
Soju	50ml	17%	~6.7g
Beer	200ml	5%	~7.9g
Wine	150ml	12%	~14.2g
Whiskey (1 shot)	30ml	40%	~9.5g

Legal Driving Limits by Country (BAC)

Country	Legal Limit	Note
South Korea	0.03% or above	Tightened in 2019
United States	0.08% or above	Common baseline (varies by state; some use lower limits for certain drivers)
Japan	0.03% or above	Penalties can apply at even lower levels

This table is for reference only — always check current local law for exact legal limits and penalties.

Frequently asked questions

Can I use this result to decide if it is safe to drive?

No, never. This calculator produces only a rough estimate from a simplified average formula, and it can differ from your actual BAC. Whether it is safe to drive must be determined by an approved method such as a breathalyzer or blood test — if you have had any alcohol at all, the safest choice is not to drive.

Why is the calculation different for men and women?

The Widmark formula uses a body-water distribution constant (r). On average, women have a higher body fat percentage and lower proportion of body water than men, so the same amount of alcohol tends to produce a higher BAC. This is a statistical average and individual variation is significant.

Why does the number go down over time?

The formula assumes the liver eliminates alcohol at an average rate of about 0.015% per hour. Actual elimination rates vary by person and by circumstance (e.g. fasting, fatigue, illness).

Does eating food while drinking change the result?

In reality, yes — whether you ate, how much, and any medication you take can significantly affect absorption speed and peak BAC. This calculator does not account for those factors for the sake of simplicity, so treat the result as a rough reference only, not an exact value.