BAC Calculator
Estimate blood alcohol content using the Widmark formula with drink presets, custom inputs, eating modifier, and metabolization timeline.
Blood Alcohol Content (BAC) Calculator
Estimate your blood alcohol content using the Widmark formula. Input drinks consumed, body weight, sex, and time elapsed to get BAC estimates, legal status, effects, and a metabolization timeline.
Important Disclaimer
This is an estimate only. BAC varies by metabolism, food, medications, tolerance, and individual factors. Never drive if you have been drinking. When in doubt, do not drive.
Personal Details
Body water constant: male = 0.68, female = 0.55
Drinks Consumed
Beer
12 oz, 5% ABV
Wine
5 oz, 12% ABV
Shot
1.5 oz, 40% ABV
Cocktail
6 oz, 15% ABV
How It Works
This calculator uses the Widmark formula to estimate blood alcohol content:
- r = body water constant (male: 0.68, female: 0.55)
- alcohol_grams = volume_ml x (ABV / 100) x 0.789 (density of ethanol)
- 0.015 = average BAC elimination rate per hour
- Eating modifier: reduces absorption by ~20% (multiplies by 0.8)
- Standard drink: US = 14 g alcohol, AU/UK = 10 g alcohol
Important Disclaimer
This is an estimate only. BAC varies by metabolism, food, medications, tolerance, and individual factors. Never drive if you have been drinking. When in doubt, do not drive. This tool is for educational purposes and does not constitute medical or legal advice.
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Frequently Asked Questions
What is the BAC Calculator?
The BAC Calculator is a free online tool that estimate blood alcohol content using the widmark formula with drink presets, custom inputs, eating modifier, and metabolization timeline.. It runs entirely in your browser with no installation or sign-up needed.
How does the Widmark formula work?
BAC = (alcohol grams / (body weight grams x body water constant)) - (0.015 x hours). Body water: male 0.68, female 0.55.
Is it accurate?
Estimate only. Actual BAC varies by metabolism, food, medications, tolerance. Never rely on any calculator to determine if safe to drive.
What drink presets?
Beer (12oz/5%), Wine (5oz/12%), Shot (1.5oz/40%), Cocktail (6oz/15%), plus custom volume + ABV input and standard drink counting.
Is the BAC Calculator free to use?
Yes, the BAC Calculator is 100% free with no registration, no hidden fees, and no usage limits. All processing happens locally in your browser, ensuring complete privacy.
Is my data safe with this tool?
Absolutely. The BAC Calculator processes everything client-side in your browser. No data is uploaded to or stored on any server. Your content remains private on your device at all times.
Does the BAC Calculator work on mobile devices?
Yes, the BAC Calculator is fully responsive and works on smartphones and tablets. You can use it on any device with a modern web browser -- no app download required.
Do I need to create an account to use this tool?
No account or registration is needed. Simply open the BAC Calculator in your browser and start using it immediately. There are no sign-up walls or usage restrictions.
How do I use the BAC Calculator?
Simply enter your input in the provided field, adjust any settings to your preference, and the tool will process it instantly. You can then copy the result to your clipboard or download it.
Which browsers are supported?
The BAC Calculator works in all modern browsers including Chrome, Firefox, Safari, Edge, and Opera. For the best experience, use the latest version of your preferred browser.
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About BAC Calculator
BAC Calculator is a free, browser-based tool in our Calculator Tools collection. Everything runs locally on your device — no uploads, no sign-up, and your data stays private.