How is BAC calculated?

BAC is estimated using the Widmark formula: BAC = (Alcohol consumed in grams / (Body weight in grams x r)) - (0.015 x hours since drinking), where r is a gender-based constant (0.68 for men, 0.55 for women).

Is the BAC estimate accurate?

BAC calculators provide estimates only. Actual BAC depends on many factors including metabolism, food consumption, medications, liver health, and individual tolerance. Never rely on a calculator to determine if you are safe to drive.

What BAC level is considered legally impaired?

In most US states, the legal limit is 0.08% BAC for drivers over 21. Many countries have lower limits (0.05% or even 0.02%). Impairment can begin at BAC levels as low as 0.02%.

Blood Alcohol Calculator (BAC)

Estimate your blood alcohol content based on drinks consumed, body weight, gender, food intake, and time elapsed. Uses the Widmark formula with food absorption factors.

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Gender

Weight

Hours Elapsed

🍽️ Stomach Contents

🍹 Drinks Consumed

🍺

Beer

355ml / 5% ABV

😌

Estimated BAC

0.036%

Light

Lowered inhibitions, mild euphoria, slight reasoning impairment.

⏰

~2.4h

Time to Sober

🥃

2.0

Standard Drinks

🔥

~196

Calories

⚗️

28g

Pure Alcohol

⏰ Estimated Sober At

20:42

~2h 25m remaining

📉 Sobriety Timeline

1.0h

0.036

1.5h

0.029

2.0h

0.021

2.5h

0.014

3.0h

0.006

3.5h

0.000

✓ Estimated sober at +3.4 hours

⚠️ Disclaimer: This calculator provides estimates only using the Widmark formula. Actual BAC depends on many factors including metabolism, medications, hydration, liver health, and individual biology. Never rely on a calculator to determine if you are safe to drive. When in doubt, do not drive.

ℹ️ How BAC is Calculated

This calculator uses the Widmark formula with food absorption modifiers:

Total alcohol consumed (grams) = Volume x ABV x 0.789 (ethanol density)
Body water distribution: 0.68 for males, 0.55 for females
Metabolic elimination: ~0.015% BAC/hour
Food absorption: empty stomach = 100%, light snack = 85%, full meal = 65%
One standard drink = 14g pure alcohol (12 oz beer at 5%, 5 oz wine at 12%, or 1.5 oz spirits at 40%)

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