What is the Widmark equation?
The Widmark equation estimates blood alcohol concentration from alcohol consumed, body weight, and a distribution factor. It is a starting point, not a full BAC timeline.
What The Widmark Equation Uses
- Alcohol dose: the amount of ethanol consumed, often converted from beverage volume and alcohol concentration.
- Body weight: the subject's weight, converted into a mass basis for the estimate.
- Distribution factor: an assumption about how alcohol distributes through body water.
Why A Calculator Is Not The Whole Analysis
A simple Widmark calculation does not fully answer when drinking occurred, how quickly alcohol was absorbed, whether the person was post-absorptive, what elimination rate is appropriate, or whether a measured result is consistent with the reported timeline. DUI Professional uses Widmark-based concepts inside a broader timeline workflow.
Interactive Simplified Example
Adjust the number of standard drinks and distribution assumption to see how a simplified estimate changes for a 180 lb person before metabolism is deducted.
Approximate peak BAC before metabolism: 0.03%
Professional Use In DUI And Forensic Review
Attorneys and experts can use Widmark-based estimates to frame questions, but professional analysis should document the assumptions used and the limits of the calculation. Scenario modeling helps show how the estimate changes when timing, absorption, and elimination assumptions change.
DUI Professional does not determine guilt, impairment, admissibility, or the legal sufficiency of evidence. It provides structured BAC scenario modeling and report support for qualified professional review.
Frequently Asked Questions
What is the Widmark equation?
The Widmark equation estimates BAC from alcohol amount, body weight, and a distribution factor.
What does the Widmark equation leave out?
By itself, it does not fully model drinking duration, absorption timing, elimination, specimen issues, or individual uncertainty.
Why use BAC simulation with Widmark concepts?
Simulation helps show how timing, absorption, elimination, and uncertainty can change the estimated BAC curve.
Move from a simple BAC estimate to a full timeline
Use DUI Professional to compare Widmark-based estimates with absorption, elimination, and key case times.
Sources
These references support the scientific and forensic context discussed on this page.
- ANSI/ASB Best Practice Recommendation 122, First Edition 2024 Current forensic alcohol calculation guidance for assumption-based alcohol calculations, reporting, specimen considerations, and limitations.
- NIAAA, Alcohol Metabolism Ethanol metabolism, ADH and ALDH pathways, and individual variation in alcohol processing.
- NIAAA, Understanding Alcohol Drinking Patterns Standard drink and drinking-pattern context for alcohol education.
