Health & FitnessFormula-based · Runs in your browser

BAC Calculator

Estimate blood alcohol concentration from detailed beer, wine, spirit, and custom beverage amounts using a Widmark-style model.

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Inputs

Enter the values you know. Optional fields may be left empty.

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Required
Required
Required
lb
Required
hours
Required
Required
fl oz
Required
% ABV
Required
Required
fl oz
Required
% ABV
Required
Required
fl oz
Required
% ABV
Required
fl oz
Required
% ABV
Required
BAC/hour

Result

Updates as valid inputs change.

Calculated locally
Never use a BAC estimate to decide whether to drive, operate equipment, supervise others, or delay emergency care. Actual BAC can be higher or lower.
Estimated current BAC
Estimated pre-elimination BAC
Approximate U.S. standard drinks
Pure alcohol consumed
Additional estimated time to zero
Safety message

Saved locally, explained clearly

Drafts, calculations, scenarios, and workflow progress stay in this browser unless you export them.

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Calculation steps

Follow what happened from the selected formula to the displayed answer.

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  1. 1

    Formula selected

    The calculator uses the following formula or method.

    Alcohol grams = volume × ABV × ethanol density; Widmark-style BAC = alcohol grams ÷ (distribution factor × body mass grams) × 100 − elimination rate × hours.

  2. 2

    Values entered

    Your values are placed into the calculation.

    Enter values to see what is used in this step.

  3. 3

    Result calculated

    The formula or method produces the following result values.

    Results will appear after a successful calculation.

  4. 4

    Answer formatted

    Displayed values are rounded and formatted using each output’s configured precision.

Scenario comparison

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Recent calculations

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Data and privacy

How it works

Beer, wine, spirits, and a custom beverage are converted to grams of pure ethanol using serving volume, ABV, and ethanol density. A Widmark-style distribution model then subtracts an assumed hourly elimination amount.

Input query strings and outputs

Use an input name in this page’s URL as ?name=value, and join additional inputs with &. Portable shared links may instead use the compact ?ac= state parameter.

Input query strings

17
  • ?unitSystem= Body-weight units

    Choice · Required · Default: imperial · Accepted values: imperial, metric

  • ?sex= Sex-based distribution factor

    Choice · Required · Default: male · Accepted values: male, female

  • ?weightLb= Body weight

    Number · Required · Default: 180 · Used when unitSystem = imperial

  • ?weightKg= Body weight

    Number · Required · Default: 82 · Used when unitSystem = metric

  • ?hoursSinceFirstDrink= Hours since first drink

    Number · Required · Default: 2

  • ?beerCount= Beer servings

    Number · Required · Default: 3

  • ?beerSizeOz= Beer serving size

    Number · Required · Default: 12

  • ?beerAbv= Beer alcohol

    Percentage · Required · Default: 5

  • ?wineCount= Wine servings

    Number · Required · Default: 0

  • ?wineSizeOz= Wine serving size

    Number · Required · Default: 5

  • ?wineAbv= Wine alcohol

    Percentage · Required · Default: 12

  • ?spiritCount= Spirit servings

    Number · Required · Default: 0

  • ?spiritSizeOz= Spirit serving size

    Number · Required · Default: 1.5

  • ?spiritAbv= Spirit alcohol

    Percentage · Required · Default: 40

  • ?otherVolumeOz= Other beverage total volume

    Number · Required · Default: 0

  • ?otherAbv= Other beverage alcohol

    Percentage · Required · Default: 0

  • ?metabolismRate= Assumed elimination rate

    Number · Required · Default: 0.015

Outputs

6
  • estimatedBac Estimated current BAC

    Percentage · Primary output

  • peakBac Estimated pre-elimination BAC

    Percentage

  • standardDrinks Approximate U.S. standard drinks

    Number

  • alcoholGrams Pure alcohol consumed

    Number · Suffix: g

  • hoursToZero Additional estimated time to zero

    Number · Suffix: hours

  • safetyMessage Safety message

    Text

Safety warning

This is not a breathalyzer or laboratory measurement. Never use the estimate as permission to drive or to delay help for suspected alcohol poisoning.

Sources
Limitations
  • Never use a BAC estimate to decide whether to drive, operate equipment, supervise others, or delay emergency care. Actual BAC can be higher or lower.
  • Health results are educational estimates, not a diagnosis or treatment recommendation. Individual circumstances may require a qualified clinician's assessment.