Formula Used
This calculator uses a simplified Widmark style estimate.
It first converts drink entries into grams of pure alcohol.
Then it estimates peak BAC before elimination.
Pure alcohol grams = volume mL × servings × ABV × 0.78924
Peak BAC % = alcohol grams ÷ (body weight grams × r) × 100
Current BAC % = peak BAC − metabolism rate × elapsed hours
Time to target = (current BAC − target BAC) ÷ metabolism rate
The value r is a body water distribution factor.
The default metabolism rate is editable.
Personal results can differ because food, health, medicine, genetics,
tolerance, sleep, and drink timing all matter.
Understanding Alcohol Metabolism Time
What the Calculator Estimates
Alcohol metabolism time is an estimate of how long your body may need
to lower blood alcohol concentration. The value is not a promise.
It is a planning number only. BAC can rise after the final drink.
This happens because alcohol absorption may continue for a while.
The calculator therefore shows a current estimate and a conservative
estimate when recent drinking may still be absorbing.
Why Drink Size Matters
A drink is not always equal to one drink. A small pour of strong liquor
can contain more alcohol than a large low strength beer. The calculator
handles this by using grams of pure alcohol. Standard drink mode is
fast. Custom drink mode is more flexible. It uses volume, servings,
and alcohol by volume. This is useful for cocktails, craft beer,
fortified wine, and mixed containers.
Why Body Weight Matters
Alcohol spreads through body water. Larger bodies often dilute the same
alcohol amount more than smaller bodies. The Widmark factor represents
that distribution. The default factors are only general estimates.
They are not medical measurements. Hydration, lean mass, body fat,
age, and individual biology can all shift the true value.
Why Time Is Important
The liver removes alcohol gradually. The common planning rate is
about 0.015 BAC percentage points per hour. Some people clear alcohol
slower. Others clear it faster. You can change the rate if your use
case needs a conservative estimate. Lower rates create longer clearance
times. That is often safer for planning.
Planning With Caution
This tool should not decide whether someone is safe to drive, work,
swim, operate tools, or take medicine. Real impairment can remain even
when a number looks lower. Sleep loss can also worsen impairment.
Food can delay absorption. Medication can increase risk. A breath,
blood, or professional test is more reliable than a web estimate.
Using the Output
Read the current BAC estimate first. Then review the target time and
zero time. If the conservative time is longer, treat it seriously.
Export the result if you need a record for education or planning.
Never use the result to override local law, medical advice, or common
safety judgment. When in doubt, wait longer and avoid risky tasks.
FAQs
1. What does this calculator measure?
It estimates current BAC and the time needed to reach a target BAC. It can use drink details or a known BAC value.
2. Is the result exact?
No. It is an estimate. Real results vary with biology, food, medicine, timing, and drink strength.
3. Can this prove I am safe to drive?
No. Do not use this page for driving clearance. Laws, impairment, and test results can differ from estimates.
4. What is the default metabolism rate?
The default rate is 0.015 BAC percentage points per hour. You can adjust it for conservative planning.
5. What is a standard drink here?
The default is 14 grams of pure alcohol. You can change this value for other standards or local definitions.
6. Why is ABV important?
ABV tells how much alcohol is inside the drink. Higher ABV means more alcohol grams in the same volume.
7. Why enter drinking duration?
Duration affects how much alcohol may already be metabolized. Longer drinking periods usually lower the current estimate.
8. Why enter time since last drink?
This helps estimate alcohol already cleared. It also warns when absorption may still be happening.
9. What is absorption delay?
It is a rough delay before BAC may peak after drinking stops. Food and drink speed can change it.
10. What is the Widmark factor?
It estimates alcohol distribution through body water. The calculator offers common values and a custom option.
11. Should I choose male or female factor?
Choose the factor that best fits your body composition estimate. Use custom only when you know a better value.
12. Why does the conservative time differ?
It adds possible extra time when alcohol may still be absorbing. This can happen soon after the final drink.
13. Can food change the result?
Yes. Food can slow absorption and shift peak timing. The calculator cannot model every meal pattern.
14. Can I export my result?
Yes. Use the CSV button for spreadsheet data. Use the PDF button for a simple report.