EtG Calculator

Written by Great Medico

Updated September 24, 2026 •2 min read

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When alcohol, nicotine, or another substance is involved, precision can be misleading. EtG Calculator gives a structured estimate from the data entered while keeping its clinical limits in view.

What this calculator does

EtG Calculator uses Sex, Number of standard drinks, Body weight, and Time since last drink to calculate the plugin’s estimated EtG level. It is built around the exact fields displayed in this plugin rather than a generic version of the topic. Where supported, it also shows Estimated initial EtG, Time to clear below 500 ng/mL, and Time to clear to 0 ng/mL so the primary result is easier to place in context. Substance-use calculators can organize exposure or screening information, but they cannot determine impairment, withdrawal safety, diagnosis, or prognosis on their own. When there is risk of overdose or dangerous withdrawal, clinical care takes priority over the score.

How to use it

Enter or select Sex, Number of standard drinks, Body weight, and Time since last drink. Use the units offered by the calculator and choose the option that matches the actual clinical or timing situation. Check date entries and laboratory units before relying on the output. Keep amounts, dates, and questionnaire answers within the same exposure or screening timeframe requested by the tool.

How the calculation works

This calculator uses a simplified linear model. It estimates an initial EtG concentration from number of standard drinks, body weight, and sex, then subtracts a fixed 150 ng/mL for every hour since the last drink, never allowing the estimate to drop below zero. It also projects time to below 500 ng/mL and to zero under that same fixed elimination assumption.

Example

Using the sample values prefilled in this calculator, the primary result is 1104.6 ng/mL (Estimated current EtG), Estimated initial EtG is 1,255 ng/mL, and Time to clear below 500 ng/mL is 4.03 h. This worked example shows how the plugin’s own default inputs flow through the implemented method; replace them with the correct patient, laboratory, imaging, or personal values before interpreting a result.

How to interpret the result

This output is only the plugin’s simplified EtG estimate under a fixed linear elimination assumption. It should not be interpreted as a predicted laboratory value, detection window, or evidence that a future EtG test will be positive or negative.

Limitations and notes

This linear EtG model is intentionally rough and is not a validated pharmacokinetic prediction. Urine EtG depends on dose, time, hydration, kidney function, assay cutoff, specimen type, and incidental alcohol exposure. Do not use the estimate to predict whether a laboratory or forensic test will be positive.