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Blood Alcohol Content (BAC) Calculator

Estimate blood alcohol level using the Widmark formula. For educational purposes only — never use to determine fitness to drive.

⚠️ Estimated BAC above 0.08% — Do NOT drive. Call a rideshare.

1 drink = 12oz beer, 5oz wine, or 1.5oz spirits

BAC Estimate

1.818%

Estimated Blood Alcohol Content

Severely Impaired

Level

121.2h

Hours to Sober

0.080%

Legal Limit (US)

🚫 Do Not Drive

Status

Estimated BAC: 1.818% — Severely Impaired. Your body metabolizes ~0.015% per hour. You'll be sober in ~121.2 hours.

Analysis & insights

Your estimated BAC is 1.818%, which would take approximately 121.2 hours to return to zero at the average elimination rate of 0.015%/hour. This is above the US legal driving limit of 0.08% — DO NOT operate any vehicle. Call a rideshare or stay where you are. Critical: this calculator is a rough estimate. Your actual BAC varies by ±30% based on individual factors. Never use a calculator to decide whether to drive.

Severe impairment

Significant motor function loss, vomiting risk, blackout risk. Medical concern at 0.30%+.

Risk & benchmark gauge

Current band

Severe

BAC: 1.818%

0255075100
SoberMildModerateAbove legalSevere

Industry benchmarks

  • Your estimated BAC1.818%
  • No effects threshold0.020%
  • Buzzed driving (NHTSA)0.040%
  • US legal limit (drive)0.080%
  • Severe impairment0.150%+
  • Hours until sober121.2 hrs

Key insights

This is an ESTIMATE, not a measurement

The Widmark formula gives a population-average BAC. Your actual BAC varies by ±30% based on stomach contents, body composition, medications, and individual liver function. Never rely on a calculator to decide whether to drive.

You eliminate alcohol at a constant rate

The average adult metabolizes about 0.015% per hour. Coffee, cold showers, and food do NOT speed this up — only time.

Impairment starts well below 0.08%

Studies show measurable impairment in reaction time, lane control, and judgment as low as 0.02%. The legal limit is the LEGAL line, not the SAFE line.

Recommended actions(4)

If you've been drinking AT ALL, do not drive

High priority

Use Uber, Lyft, public transit, designated driver, or stay where you are. The cost of a ride is dramatically less than a DUI ($10K+) or a fatality.

Impact: A first-offense DUI typically costs $10,000-15,000 in fines, legal fees, insurance hikes, and lost wages.

Wait 122 hours before driving

High priority

At your estimated BAC of 1.818%, you need roughly 121.2 hours to drop to 0.0%. Add a buffer.

Impact: Even after BAC drops to zero, hangover impairment persists for additional hours.

Drink water alongside alcohol

Medium priority

Slows absorption, reduces hangover severity, and gives you a natural pacing mechanism. Aim for 1 glass of water per alcoholic drink.

This tool is for informational purposes only and does not constitute medical advice. Consult a healthcare professional for advice specific to your situation.