Using the BAC Calculator
Total drink volume is measured in milliliters, and ABV is the percentage printed for the drink. For multiple drinks at different strengths, a single volume-and-ABV entry needs an equivalent combined alcohol amount. The model then applies fixed distribution and elimination assumptions.
Worked example
Use the example inputs below to reproduce this result. These are the form's starting values, not recommended targets. Changing your inputs updates your result above; this worked example stays fixed for comparison. Results are rounded for display.
Example inputs
- Sex used by the equation
- Male
- Weight (kg)
- 75
- Total drink volume (mL)
- 500
- Alcohol by volume (%)
- 5
- Hours since drinking began
- 1
Example result
- Estimated BAC (%)
- 0.023676471
- Alcohol consumed (g)
- 19.725
Method and assumptions
Widmark estimate with assumed distribution factors and 0.015 percentage points/hour elimination. Absorption, food, medications and individual variation are not modeled. Never use the result to decide whether it is safe or legal to drive.
Do not turn an estimate into a driving decision
The model cannot measure absorption, impairment or a person's actual elimination rate. Waiting until a calculated value reaches zero does not verify sobriety. The elapsed-time input is part of a simplified equation, not a countdown to safe driving. Plan transportation independently of the displayed estimate.
Common question
Is this equivalent to a breath or blood test?
No. It estimates a value from reported inputs and fixed assumptions. It cannot measure your actual blood alcohol concentration, assess impairment or verify a legal threshold. Arrange transport that does not require you to drive after drinking.
Guide updated .