EtG Calculator
Estimate how long EtG stays detectable in your urine based on drinks consumed and test cutoff.
Estimate your Ethyl Glucuronide (EtG) urine levels based on standard metabolization rates and a typical 3-hour half-life, using the standard 500 ng/mL testing cutoff.
An EtG calculator estimates how long ethyl glucuronide — the direct metabolite your liver produces when processing alcohol — remains detectable in your urine. Unlike a BAC calculator, which tells you when alcohol leaves your bloodstream, an EtG calculator focuses on the urine detection window that kicks in after you’d otherwise test negative for alcohol itself. That window can stretch from 24 to 80 hours, which is why EtG testing is used in probation, court-ordered monitoring, and workplace alcohol screening programs where sobriety needs to be verified days after the fact.
What Is EtG and Why Does It Stay in Urine So Long?
When your liver metabolizes ethanol, a small fraction — less than 0.1% — gets converted into ethyl glucuronide (EtG), which then filters into urine through the kidneys. EtG is a direct, stable alcohol biomarker, meaning it’s not produced by anything except alcohol metabolism. Its half-life in urine is roughly 2.5 to 5 hours, but because peak concentrations can reach tens of thousands of ng/mL after heavy drinking, it takes many half-life cycles before levels fall below any standard cutoff threshold.
That’s the core reason the detection window is so much longer than alcohol itself: the starting concentration is high, and the elimination is gradual. EtG doesn’t “disappear” — it declines in steps until it crosses below whatever ng/mL cutoff your testing program uses.
EtG Detection Window by Drinks and Cutoff Level
The single most important variable is the cutoff threshold your lab uses. The same drinking scenario produces very different results at 100 ng/mL versus 500 ng/mL. The table below shows realistic detection windows based on published elimination research — not worst-case theoretical maximums.
| Drinks Consumed | 500 ng/mL Cutoff | 300 ng/mL Cutoff | 100 ng/mL Cutoff |
|---|---|---|---|
| 1 standard drink | 12–24 hours | 18–30 hours | 24–36 hours |
| 2–3 drinks | 24–36 hours | 30–42 hours | 36–54 hours |
| 4–6 drinks | 36–54 hours | 48–60 hours | 54–72 hours |
| 6+ drinks (heavy) | 60–72 hours | 66–78 hours | 72–80+ hours |
The widely cited “80-hour window” represents the maximum for heavy drinking at a 100 ng/mL cutoff — not a typical result for moderate consumption. At the more common 500 ng/mL threshold, most people who had 1–2 drinks the previous evening will test negative within 24–36 hours.
EtG Cutoff Levels Explained
Labs don’t simply detect “EtG present or absent” — they compare your sample against a predetermined concentration threshold. The cutoff determines how sensitive the test is, and different programs use different standards:
| Cutoff Level | Common Use | False Positive Risk | Notes |
|---|---|---|---|
| 100 ng/mL | Strict probation, abstinence monitoring | Higher — incidental exposure can trigger | May detect mouthwash, hand sanitizer |
| 300 ng/mL | Clinical treatment programs | Moderate | Balance between sensitivity and specificity |
| 500 ng/mL | Workplace, DOT, legal compliance | Lower (~3%) | Most common U.S. standard; preferred in court settings |
| 1,000 ng/mL | Some employer programs | Very low | Only detects significant consumption |
A result above 500 ng/mL is generally interpreted as evidence of intentional drinking, not incidental exposure. At 100 ng/mL, the same result carries more ambiguity — which is why many court programs pair EtG testing with EtS (ethyl sulfate) to confirm specificity.
What the Calculator Takes Into Account
The EtG calculator estimates your current EtG concentration and the hours remaining until you fall below your target cutoff. To do this accurately, it needs:
- Number of standard drinks — one standard drink is 14 grams of pure alcohol: a 12 oz regular beer, a 5 oz glass of wine, or 1.5 oz of 80-proof spirits.
- Body weight — alcohol distributes through body water. Heavier individuals have more body water, which dilutes alcohol concentration and affects the EtG peak.
- Biological sex — women typically have a higher body fat percentage and lower body water ratio (~55% vs ~68% for men), which concentrates alcohol and EtG at equivalent drink levels.
- Hours since last drink — determines how far along the elimination curve you currently are.
- Target cutoff threshold — 100, 300, or 500 ng/mL depending on your testing program.
What the Calculator Cannot Tell You
EtG calculators work from population averages. Real-world results vary significantly because of factors no calculator can measure: individual liver enzyme activity, kidney function, whether the urine sample is dilute or concentrated, and the specific lab methodology in use. Published studies show that individual EtG results can fall 30–50% above or below the population average for identical drinking scenarios.
The calculator is a planning and awareness tool — not a guarantee of passing or failing any specific test.
Where EtG Testing Is Used
- Probation and court-ordered sobriety monitoring — the extended detection window makes EtG the standard for verifying abstinence between scheduled hearings.
- DUI/DWI compliance programs — drivers required to prove sobriety are often tested with EtG specifically because BAC tests would return negative within hours.
- Inpatient and outpatient addiction treatment — programs use EtG to confirm abstinence as part of structured recovery milestones.
- Workplace alcohol screening — some employers run EtG panels alongside standard drug screens, particularly in safety-sensitive industries.
- Child custody cases — family courts increasingly use EtG testing when alcohol use is a material concern in custody determinations.
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EtG detection time depends on how much alcohol was consumed and the cutoff level of the test. After light drinking (1–2 drinks), EtG typically clears within 24–36 hours at a 100 ng/mL cutoff. After heavy drinking (7+ drinks), EtG can remain detectable for up to 72–80 hours. The commonly cited "80-hour window" applies to heavy, not casual, consumption.
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At sensitive cutoffs like 100 ng/mL, incidental alcohol exposure from mouthwash, hand sanitizer, or certain medications has been documented to produce positive EtG results. At the 500 ng/mL cutoff, incidental exposure is very unlikely to trigger a positive. Knowing your program's specific threshold is essential if you're concerned about non-beverage alcohol sources.
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A breathalyzer measures current blood alcohol concentration — it only detects active intoxication within a few hours of drinking. EtG is a metabolite that lingers in urine long after alcohol has cleared the bloodstream, making it useful for detecting drinking that occurred days earlier. EtG does not measure impairment; it confirms whether alcohol was consumed recently.
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Drinking water dilutes urine, which lowers the measured EtG concentration — but it does not speed up the actual metabolism or elimination of EtG from the body. Most testing programs include specimen validity checks (creatinine and specific gravity) that flag diluted samples, which can result in a rejected specimen or be treated as a failed test. Dilution is not a reliable strategy.