What is the legal BAC limit for driving?

In the US and UK the legal limit is 0.08% BAC. In Australia and most of Europe it is 0.05%. Some countries have zero tolerance (0.00%). These are legal limits, not safety limits — impairment begins at 0.02%.

How long does it take to sober up?

The body metabolises alcohol at roughly 0.015% BAC per hour. Coffee, food, and exercise do not speed this up. Only time reduces BAC.

Blood Alcohol Calculator (BAC)

Estimate your Blood Alcohol Content using the Widmark formula. Enter drinks, weight, and time elapsed.

Biological sex

Male

Female

Weight unit

lbs

Body weight (kg)

Standard drinks consumed

1 standard drink = 14g alcohol (355ml beer, 148ml wine, 44ml spirits)

Hours since first drink

Estimated BAC

0.000%

Sober

BAC reference levels

BAC	Level	Effects
0.02%	Subtle effects	Slight relaxation, mild mood elevation.
0.05%	Mild impairment	Reduced inhibitions, impaired judgment.
0.08%	Legal limit (US/UK)	Impaired coordination, reasoning, and reaction time.
0.15%	Significant impairment	Slurred speech, loss of balance.
0.30%	Potentially fatal	Stupor, possible coma.

This calculator provides an estimate only. Actual BAC varies with food intake, medications, and individual metabolism. Never drive after drinking, regardless of estimated BAC.

Blood Alcohol Content (BAC) Calculator

The BAC Calculator uses the Widmark formula to estimate blood alcohol concentration based on drinks consumed, body weight, biological sex, and time elapsed since drinking.

Widmark formula

BAC = (drinks × 14g) ÷ (weight_kg × r × 1000) − 0.015 × hours
r = 0.73 for males (higher body water content dilutes alcohol)
r = 0.66 for females
Metabolism rate: −0.015% BAC per hour on average

What is a standard drink?

355 ml regular beer (5% ABV)
148 ml wine (12% ABV)
44 ml spirits (40% ABV)

Legal limits

Most countries set the drink-drive limit at 0.08% BAC (US, UK, Canada) or 0.05% (Australia, most of Europe). Some countries have zero tolerance (0.00%).