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Blood alcohol estimate calculator
Estimate alcohol concentration from alcohol mass, body weight and distribution ratio.
On this page
Estimated BAC0.02%
Calculator controls
How to calculate
Estimate alcohol concentration from alcohol mass, body weight and distribution ratio.
Estimated BAC = alcohol/(weight*1000*ratio)*100-hours*elimination
Worked example
Alcohol consumed (grams): 28; Body weight (kg): 75; Distribution ratio: 0.68; Hours since drinking began: 2; Elimination / hour (%): 0.015.
Estimated BAC: 0.02 %.
Assumptions and limits
This rough model cannot determine impairment, fitness to drive or legal status. Absorption and elimination vary. Never use it to decide whether to drive.
Results are rounded for display; calculations use unrounded values. Read our calculation methodology.
Understanding the result
Estimate alcohol concentration from alcohol mass, body weight and distribution ratio. The displayed figures use the inputs and formula shown on this page.
When this tool is useful
Use the blood alcohol estimate to compare a scenario, check an estimate, or verify a manual calculation.
Understanding your inputs
| Input | What to enter |
|---|---|
| Alcohol consumed (grams) | Enter a number of at least 0 and no more than 1000. |
| Body weight (kg) | Enter a number of at least 0.000001 and no more than 1000000000000. |
| Distribution ratio | Enter a number of at least 0.3 and no more than 1. |
| Hours since drinking began | Enter a number of at least 0 and no more than 48. |
| Elimination / hour (%) | Enter a number of at least 0 and no more than 0.1. |
Frequently asked questions
What should I check before using the blood alcohol estimate result?
This rough model cannot determine impairment, fitness to drive or legal status. Absorption and elimination vary. Never use it to decide whether to drive.
Is this blood alcohol estimate result exact?
It is exact for the stated mathematical model and entered values. Real-world results can differ when rates, timing, fees, definitions or measurement conditions differ.