Alcohol BAC Timeline Calculator
Blood alcohol level and time to sober up.
Enter your values
Choose one of: Male, Female.
Enter the weight in kg.
Enter the standard drinks (14g alcohol each) you are working with.
Enter the hours since first drink in hours.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Estimated BAC
- 0.073%
- Hours until sober (BAC 0)
- 4.9
- Legal driving limit note
- Common limit is 0.05-0.08% — check your local law
Quick answer
Blood alcohol content is estimated from alcohol consumed, body weight, sex and time elapsed, using the Widmark formula.
BAC = (alcohol grams / (weight(g) x r)) - 0.015 x hours
At a glance
| What it does | Blood alcohol level and time to sober up. |
|---|---|
| Category | Health |
| Inputs needed | Sex, Weight, Standard drinks (14g alcohol each), Hours since first drink |
| Main output | Estimated BAC |
| Formula | BAC = (alcohol grams / (weight(g) x r)) - 0.015 x hours |
| Cost | Free — no sign-up, no download |
How to use the Alcohol BAC Timeline Calculator
- 1Enter sex, weight, number of standard drinks and time elapsed since your first drink.
- 2The Widmark formula is a population estimate and can be significantly off for a given individual due to metabolism, food intake and drink strength.
- 3Never use this to decide whether it is safe to drive — BAC estimates are not reliable enough for that decision. If in doubt, do not drive.
Inputs explained
- Sex
- Choose one of: Male, Female.
- Weight(kg)
- Enter the weight in kg.
- Standard drinks (14g alcohol each)
- Enter the standard drinks (14g alcohol each) you are working with.
- Hours since first drink(hours)
- Enter the hours since first drink in hours.
Worked example
Using the values the calculator loads with:
Inputs
- SexMale
- Weight80 kg
- Standard drinks (14g alcohol each)4
- Hours since first drink2 hours
Results
- Estimated BAC0.073%
- Hours until sober (BAC 0)4.9
- Legal driving limit noteCommon limit is 0.05-0.08% — check your local law
Frequently asked questions
Is this accurate enough to decide if I can drive?
No — treat it purely as educational; individual variation is large and actual testing is the only reliable measure.
Does food affect BAC?
Yes, food slows alcohol absorption and can lower peak BAC, which this simple formula does not fully capture.
What do I need to enter into the Alcohol BAC Timeline Calculator?
Just 4 values: sex, weight, standard drinks (14g alcohol each), hours since first drink. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Alcohol BAC Timeline Calculator work out the answer?
Blood alcohol content is estimated from alcohol consumed, body weight, sex and time elapsed, using the Widmark formula. It applies the formula BAC = (alcohol grams / (weight(g) x r)) - 0.015 x hours and shows the working so you can check each step by hand.
Is the Alcohol BAC Timeline Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.