Blood Alcohol Content (BAC) Calculator

Estimate your blood alcohol level and understand impairment

Calculate Your BAC

Drinks Consumed

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Your BAC Estimation

Current BAC

0.00

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When Sober

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hours until BAC reaches 0.00

BAC Over Time

Impairment Levels

0.00 - 0.05%: Mild impairment - Some loss of judgment, relaxation
0.05 - 0.08%: Increased impairment - Reduced coordination, reasoning
0.08 - 0.15%: Significant impairment - Poor muscle control, slurred speech
0.15%+: Severe impairment - Risk of blackouts, loss of consciousness
Important Safety Information

Never drink and drive. In most countries, the legal limit is 0.08% BAC, but impairment begins at much lower levels. This calculator provides estimates only - many factors can affect your actual BAC. When in doubt, choose a designated driver or alternative transportation.

Understanding Blood Alcohol Content (BAC)

Blood Alcohol Content (BAC) is a measure of the amount of alcohol in your bloodstream. It's expressed as a percentage representing grams of alcohol per 100 milliliters of blood. BAC is used to determine legal intoxication levels and assess impairment.

How the BAC Calculator Works

This calculator estimates your BAC using the Widmark formula, which considers:

Factors That Affect BAC

  • Food intake: Eating slows alcohol absorption
  • Metabolism: Varies by individual
  • Medications: Can interact with alcohol
  • Tolerance: Doesn't lower BAC, just masks effects
  • Body fat percentage: Alcohol is water-soluble

Standard Drink Sizes

  • Beer: 12oz at 5% alcohol
  • Wine: 5oz at 12% alcohol
  • Liquor: 1.5oz at 40% alcohol
  • Fortified Wine: 3oz at 17% alcohol
  • Light Beer: 12oz at 4.2% alcohol

Frequently Asked Questions

This calculator provides reasonable estimates based on scientific formulas, but many individual factors can affect your actual BAC:
  • Metabolism rate varies by person
  • Food in your stomach slows absorption
  • Medications may interact with alcohol
  • Actual drink sizes often exceed "standard" sizes
  • Body composition affects alcohol distribution
Always err on the side of caution - if you've been drinking, don't drive.

Alcohol is metabolized at an average rate of about 0.015% BAC per hour (about one standard drink per hour). However:
  • This rate can vary by ±0.005% based on individual factors
  • Nothing speeds up this process (not coffee, showers, etc.)
  • Alcohol can be detected in urine for 12-48 hours after drinking
  • Hair tests can detect alcohol consumption for up to 90 days
The only way to sober up is to wait for your body to metabolize the alcohol.

No. Despite common myths, nothing speeds up alcohol metabolism:
  • Coffee only makes you a more alert drunk
  • Cold showers don't affect liver function
  • Exercise doesn't accelerate processing
  • Eating food only slows absorption, doesn't increase elimination
The liver processes alcohol at a fixed rate. The only way to lower BAC is to wait for your body to metabolize the alcohol naturally.

Legal limits vary by country and sometimes by age:
  • United States: 0.08% for adults (21+), 0.02% or zero tolerance for under 21
  • Canada: 0.08% federal, some provinces have lower limits
  • UK: 0.08% (England/Wales/NI), 0.05% (Scotland)
  • Australia: 0.05% nationwide
  • Most of Europe: 0.05% or lower
  • Japan: 0.03%
  • Some countries: Zero tolerance (any detectable alcohol)
Remember that impairment begins well below the legal limit. The safest choice is to not drive after drinking.