256 Tools

Alcohol Metabolism Calculator (BAC)

Estimate only, based on the Widmark formula. Many factors affect real blood alcohol. Never use this to decide whether to drive — it is not medical or legal advice.

Body type
Estimated BAC now
0.026%
Peak BAC
0.041%
Time until ~0.00%
1h 46m
Time until under limit
0h 0m

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This calculator estimates your blood alcohol concentration (BAC) from your weight, body type, how much you drank, and how long ago, using the well-known Widmark formula. It also estimates roughly how long until your level returns to zero or below a legal limit. It is an estimate only and not medical or legal advice. Everything runs in your browser.

Estimate only, based on the Widmark formula. Many factors affect real blood alcohol. Never use this to decide whether to drive — it is not medical or legal advice.

How to use

  1. Enter your weight and body type.
  2. Enter the drink volume, its alcohol percentage, and hours since drinking.
  3. Read the estimated BAC and rough time to clear.

How it works

The pure alcohol in a drink is its volume times the alcohol percentage times ethanol's density (about 0.789 g/ml). The Widmark formula divides those grams by your body water (weight times a factor — roughly 0.68 for men and 0.55 for women) to get the peak BAC. The body then clears alcohol at about 0.015 percentage points per hour, so the current BAC subtracts that rate times the hours elapsed.

Alcohol grams divided by body water gives BAC, which falls over time.alcohol g÷body water=BAC ↓ time

Features

BAC estimate

Estimates your current and peak blood alcohol level.

Time to clear

Rough time until your level reaches zero or a legal limit.

Widmark formula

Uses the standard formula taught in toxicology.

Private & instant

All math runs in your browser; nothing is uploaded.

When to use it

Awareness

Understand roughly how alcohol affects your body.

Planning

Get a rough idea of how long to wait — never to drive.

Learning

See how the Widmark formula works.

Comparing drinks

See how volume and ABV change the alcohol grams.

Notes

  • This is an estimate; real BAC varies with food, health, and more.
  • Clearance is assumed at 0.015 %/hour, which differs per person.
  • Never use this to decide whether it is safe to drive.
  • All calculations run on your device; nothing is uploaded.

FAQ

Is this accurate enough to drive by?
No. It is a rough estimate only and must never be used to decide whether to drive. Real BAC depends on many personal factors.
What is the Widmark formula?
A standard way to estimate BAC from alcohol grams and body water. It is widely taught but still an approximation.
Why do men and women differ?
Body water differs on average, so the formula uses a higher factor for men (about 0.68) than women (about 0.55).
How fast does alcohol clear?
Roughly 0.015 percentage points of BAC per hour on average, though it varies between people.
Is my data uploaded?
No. Everything is calculated in your browser and nothing leaves your device.

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