THE NUMORIX GUIDE
How to use the Blood Alcohol Calculator
Last reviewed September 14, 2026
What this calculator does
The engine applies a simplified Widmark-style estimate: BAC = (drinks * 14) / (weight * distribution factor) - (0.
Formula and method
The engine applies a simplified Widmark-style estimate: BAC = (drinks * 14) / (weight * distribution factor) - (0.015 * hours). It uses a distribution factor of 0.68 for the male option and 0.55 for every other option, then clamps a negative result to zero and rounds the displayed BAC to four decimals.
Variables and inputs
Drinks is a count of US-standard drinks, with 14 g of pure alcohol assumed per drink. Weight is in kilograms, hours is elapsed time since drinking, and gender selects the distribution factor. The UI accepts nonnegative drinks and hours and a positive weight.
Worked example
For 3 drinks, 75 kg, the male option, and 2 hours: (3 * 14) / (75 * 0.68) - (0.015 * 2) = 0.7935%. The engine displays 0.7935%, even though real BAC reporting and legal thresholds use different measurement conventions and individual absorption varies.
How to interpret the result
This is a rough arithmetic scenario, not a measurement of current impairment. A larger drink count raises the estimate, while the fixed elimination term lowers it with time. A zero result can mean the formula went below zero, not that alcohol has been cleared from the body.
Common mistakes to avoid
Do not count a large or strong beverage as one standard drink without checking its alcohol content. Enter kilograms rather than pounds, and count hours from the drinking period rather than from when you feel sober. Never use the result to decide whether to drive.
Assumptions and limitations
The engine does not model drink timing, food, absorption, medications, liver function, body-water variation, or measured breath or blood alcohol. Its output scale is a simplified percentage and is not a reliable legal BAC or impairment test. Do not drive after drinking; use a sober driver or another safe plan.