BAC Calculator
Standard-drink arithmetic, not a breathalyzer. Click any i for detail.
Drinks
Number of drinks
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Count
How many identical drinks. |
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Drink volume (fl oz)
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Volume
A US shot is ~1.5 fl oz; a 12 oz beer is 12. |
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ABV (%)
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ABV
Alcohol by volume. 40% is 80 proof spirits; beer is often ~5%. |
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Body weight (lb)
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Weight
Body weight in pounds. |
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Sex (Widmark r)
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r
Uses r ≈ 0.68 male / 0.55 female. This is a population sketch, not a body-composition test. |
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Hours since first drink
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Hours
Elimination sketch 0.015% BAC per hour. |
How to use this calculator
- Enter drink count, volume in fl oz, and ABV percent.
- Enter body weight in pounds and sex for Widmark r.
- Add hours since first drink for elimination sketch.
- Read estimated BAC percent. Never use this to decide to drive.
Results explained
Grams ethanol from volume × ABV × 0.789 g/mL, then Widmark distribution, minus 0.015%/hour elimination. Food, meds, and tolerance are ignored.
Quick reference: Widmark sketch
A US standard drink is about 14 g ethanol; this page uses the pour you typed.
| Item | Detail |
|---|---|
| r male | ≈ 0.68 |
| r female | ≈ 0.55 |
| Elimination | ≈ 0.015% BAC per hour (flat rate) |
| Legal limits | jurisdiction-specific; not printed here |
Not legal advice and not a breathalyzer.
How the estimate is built
BAC% ≈ 100×g / (body_g × r) − 0.015×hours.
Example scenario
Three 1.5 oz pours at 40% ABV, 180 lb male, 2 h → see live BAC% (well above zero).
FAQ
Can I drive if this is under 0.08?
Do not use this page to decide. Impairment starts below statutory limits. Use a ride.
What counts as one drink?
Adjust volume and ABV to match what you poured, not a generic label.
Why male vs female r?
Widmark used different body water fractions. It is a population sketch, not body composition.