- Model estimate
- 0.01%
- Alcohol consumed
- 14 g
About this result
This value cannot establish whether it is safe or legal to drive. The model can substantially overestimate or underestimate actual BAC.
How it works
Serving size changes alcohol exposure
A 500 mL drink at 6% ABV contains the same alcohol volume as 250 mL at 12%. Counting glasses alone misses this difference; equal alcohol amounts still do not guarantee equal measured BAC or impairment.
Why an alcohol estimate cannot establish safety
A BAC estimate models alcohol intake using the selected beverage amounts, timing, and body assumptions. Actual alcohol concentration and impairment can differ from that model. Check whether amounts describe beverage volume or alcohol content, and use the multiple-beverage mode when appropriate. Do not use the estimated concentration or time to decide whether it is safe or legal to drive.
Alcohol estimate: formula and assumptions
Alcohol grams = volume(mL) × ABV × 0.789. Estimated BAC% = grams / [weight(g) × distribution factor] × 100 − 0.015 × hours.
This simplified model assumes distribution factors 0.68 (male) and 0.55 (female). Absorption and elimination differ substantially between people.
Multiple beverages: formula and assumptions
Alcohol grams=Σ(count×mL×ABV/100×0.789); estimated BAC uses the Widmark model.
All drinks are combined under an instantaneous-absorption assumption. This cannot establish whether driving is safe or legal.
Single beverage with volume units: formula and assumptions
Alcohol grams = volume in mL × ABV/100 × 0.789; simplified BAC uses weight and an assumed distribution factor.
US and Imperial fluid ounces differ. This simplified model does not represent individual absorption, safe driving, sobriety or a legal limit.
Multiple beverages with volume units: formula and assumptions
Sum alcohol grams across beverages, then apply the simplified weight/distribution/elimination model.
This model assumes instantaneous absorption and a constant elimination rate. Fractional counts represent partial drinks. Never use the result to decide whether to drive or whether emergency care is needed.
Worked example
Using the Alcohol estimate example:
- Sex used by the equation
- Male
- Measurement system
- Metric (kg, cm)
- Weight (kg)
- 70
- Alcoholic beverage volume (mL)
- 355
- Alcohol by volume (%)
- 5
- Hours since drinking began
- 1
Alcohol grams = volume(mL) × ABV × 0.789. Estimated BAC% = grams / [weight(g) × distribution factor] × 100 − 0.015 × hours.
Example result
Model estimate: 0.01%
Alcohol consumed: 14 g
- This value cannot establish whether it is safe or legal to drive. The model can substantially overestimate or underestimate actual BAC.
These are illustrative inputs. Change the values to explore a different scenario.
What to keep in mind
Never use this estimate to decide whether to drive, operate machinery, or whether someone needs emergency care. A zero estimate does not establish sobriety.
Formula references
- NIAAA: alcohol and your health (opens in a new tab)
- NIST SP 811 Appendix B.8 conversion factors (opens in a new tab)
- NIST Handbook 44 (2026), Appendix C (opens in a new tab)
- Searle (2015), Alcohol calculations and their uncertainty (opens in a new tab)
- NIAAA, What is a standard drink? (opens in a new tab)
References explain the underlying methods; they do not imply endorsement or individual professional review of Finflo.
Common questions
Does a zero estimate mean it is safe or legal to drive?
No. A zero result does not establish sobriety. Never use this estimate to decide whether to drive or operate machinery.
Why can measured alcohol levels differ from the estimate?
Absorption and elimination vary substantially. The single-beverage mode uses hours since drinking began; the multiple-beverage mode assumes simultaneous absorption. Neither timing convention describes everyone accurately.
Prepared by Finflo. See our methodology and editorial policy. Read the relevant professional-advice limitations.