etoh calculator

What is an EToH calculator?

EToH is shorthand used in medicine for ethanol, the type of alcohol found in beer, wine, and spirits. An EToH calculator helps estimate how much ethanol you consumed and the possible effect on your blood alcohol concentration (BAC).

This calculator is useful for education, harm reduction, and planning safer choices. It is not a substitute for breathalyzer testing, clinical judgment, or legal standards.

How this calculator works

1) Estimate grams of ethanol consumed

Ethanol mass is calculated from drink count, drink volume, and ABV:

ethanol grams = drinks × volume(mL) × (ABV/100) × 0.789

The constant 0.789 is ethanol density (g/mL).

2) Estimate BAC using Widmark-style logic

BAC is approximated from ethanol grams, body weight, and a distribution factor (r):

BAC% (peak) ≈ (ethanol grams / (r × body weight grams)) × 100

• Typical r values used: 0.68 (male), 0.55 (female).
• This is a rough model and not exact for all individuals.

3) Subtract metabolic elimination over time

BAC is then reduced by an hourly metabolism estimate:

current BAC ≈ peak BAC − (elimination rate × hours)

Most calculators use around 0.015 % BAC/hour by default.

How to use the calculator correctly

• Enter your current body weight and unit.
• Choose sex to set the Widmark distribution factor.
• Use realistic drink size and ABV values (label values if possible).
• Use hours since the first drink for a conservative estimate.
• When in doubt, round up drink count and ABV for safety.

Interpreting BAC ranges (general guidance)

• 0.01–0.03%: mild effects; subtle changes.
• 0.04–0.06%: reduced judgment, lowered inhibition.
• 0.07–0.09%: clear impairment; unsafe for driving.
• 0.10–0.19%: major motor and cognitive impairment.
• 0.20%+: high risk; possible medical emergency.

Important safety notes

Even low BAC can impair reaction time. If there is any doubt, do not drive, operate machinery, swim alone, or make high-risk decisions. If someone is vomiting repeatedly, difficult to wake, confused, cold, or breathing slowly, seek emergency care immediately.

FAQ

Is this calculator accurate enough for legal decisions?

No. It is an estimate only. Legal BAC must be measured by validated testing methods.

Why can two people with the same drinks have different BAC?

Food intake, hydration, body composition, genetics, medications, drinking pace, and health status can all change absorption and elimination.

Does coffee lower BAC?

No. Caffeine may reduce sleepiness but does not speed ethanol metabolism or reduce measured BAC.