EtG Calculator
Get a rough estimate of the urine EtG (ethyl glucuronide) detection window. Enter how many standard drinks you had, hours since your last drink, and the lab cutoff (100, 250, or 500 ng/mL). This is an educated guess, not a guarantee.
Example: with Standard drinks consumed 4 · Hours since last drink 36 · Test cutoff (ng/mL) 500 ng/mL — less sensitive → Estimated detection window: About 41 hours (rough range 24 to 47 h).
- Where you are nowNear the edge of the estimated window — genuinely a coin toss
- Read thisEstimate only. Individual clearance, kidney function, fluids, and drinking pattern shift this by many hours. Do not use it to plan around a test.
Computed by the calculator below using its default values. Change any input to see your own numbers.
EtG windows are commonly quoted as roughly 24 h for light drinking up to about 80 h after heavy drinking. Real clearance varies enormously — treat any window as a wide guess.
What EtG is and why the window is fuzzy
Ethyl glucuronide (EtG) is a minor breakdown product of alcohol. Your body makes it only when alcohol is present, so a positive urine EtG says alcohol was in your system recently. It lingers far longer than alcohol itself, which is why urine EtG is used for abstinence monitoring rather than to measure impairment.
The catch is that the detection window is not a fixed clock. How long EtG stays above a lab's cutoff depends on how much you drank, over what stretch of time, your kidney function, how much water you drank, and your own metabolism. Published ranges run from roughly a day after light drinking to around 80 hours after heavy, prolonged drinking. Lower cutoffs stretch the window; higher cutoffs shorten it.
Why you cannot game a test with this
Because the biology varies so much between people and even between days, no calculator can tell you that you will be clear by a certain hour. The same drinks can read positive in one person and negative in another at the identical time point. Lower cutoffs also pick up incidental exposure from mouthwash, hand sanitizer, and some foods. Use this page to understand the science, never to schedule drinking around a screening.
How it’s calculated
Rough model: a base window is set from amount (≤2 drinks ≈ 24 h, 3–5 ≈ 48 h, 6+ ≈ 72 h) then scaled by cutoff sensitivity (×1.15 at 100 ng/mL, ×1.0 at 250, ×0.85 at 500). The displayed low-to-high range spans 0.6× to 1.15× of that estimate. Figures are anchored to commonly cited EtG windows (about 24 to 80 hours).
This is a coarse educational estimate, not a validated pharmacokinetic model. EtG clearance varies widely with kidney function, hydration, drinking pattern, and the assay. It cannot tell you that a test will be negative.
Commonly cited EtG detection windows
| Drinking level | Typical urine EtG window |
|---|---|
| Light (1–2 drinks) | About 24 hours |
| Moderate (3–5 drinks) | About 48 hours |
| Heavy / prolonged (6+ drinks) | Up to about 72–80 hours |
| Lower cutoff (100 ng/mL) | Longer, plus incidental-exposure positives |
Source: ranges commonly reported in SAMHSA advisories and clinical toxicology literature; individual results vary widely.
Common mistakes
- Treating the estimate as a deadline — EtG clearance is not a reliable clock.
- Ignoring the cutoff; a 100 ng/mL test detects far longer than a 500 ng/mL test.
- Forgetting incidental sources (mouthwash, sanitizer, some foods) can trip low cutoffs.
- Assuming heavy hydration reliably clears you; dilution is flagged and does not guarantee a negative.
Frequently asked questions
How long does EtG stay in urine?
Commonly cited windows run from about 24 hours after light drinking to around 80 hours after heavy, prolonged drinking. Your actual window depends on amount, metabolism, kidney function, hydration, and the test's cutoff, so any single number is a rough guess.
How is the estimated window calculated here?
The tool sets a base window from the number of drinks (roughly 24, 48, or 72 hours) and scales it for the lab cutoff. It is a coarse educational model, not a measurement of your body.
Can I use this to time drinking before a test?
No. Do not use this or any calculator to plan drinking around an EtG test. The window varies so much between people that the same drinks can read positive in one person and negative in another at the same hour, and a positive can have serious consequences.
Why can I test positive without drinking?
Low cutoffs like 100 ng/mL can detect incidental alcohol from mouthwash, hand sanitizer, some medications, and fermented foods. This is one reason confirmatory testing and clinical context matter.
Who should I talk to about EtG testing?
If a test is part of monitoring, treatment, or a legal or workplace program, discuss timing, cutoffs, and any concerns with the ordering clinician or program administrator — not a calculator.