Health calculators

EtG Calculator

Updated Jul 24, 2026 By Jehan Wadia
Rate Formulas Medical disclaimer
Drink Type
Number of Drinks
Session & Test Timing
The length of your drinking session — not the time since your last drink.
Measured from now (the current moment), not from your last drink.
Body Profile
Valid range 50–500 lbs (23–227 kg).
Low Risk
EtG at test time is well below the 500 ng/mL standard cutoff.
Estimated EtG Results
Estimated EtG at Test Time
—
Estimated Peak EtG Level
—
Time to Clear 100 ng/mL (from now)
—
Estimated Clearance Hour (below 100)
—
EtG at Estimated Clearance Hour
—
Total Alcohol Consumed
—
Pass / Fail at Test Time
500 ng/mL
Standard cutoff — most common testing programs
PASS
300 ng/mL
Sensitive cutoff — enhanced monitoring programs
PASS
100 ng/mL
Strict cutoff — probation, DOT, custody contexts
PASS
Step-by-Step Solution
EtG Decline Curve & Threshold Windows

Introduction

EtG (ethyl glucuronide) is a substance your body makes after you drink alcohol. It shows up in urine tests and can be detected long after the alcohol itself is gone — sometimes up to 80 hours after your last drink. Courts, probation officers, employers, and treatment programs use EtG tests to check for recent alcohol use.

This EtG calculator estimates how much EtG may be in your system right now, at test time, or at any point in the future. Enter what you drank, how many drinks you had, your body weight, and when you stopped drinking. The calculator uses a pharmacokinetic model to estimate your peak EtG level, your EtG level at test time, and how long it will take to drop below the three most common testing cutoffs: 500 ng/mL (standard), 300 ng/mL (sensitive), and 100 ng/mL (strict).

Results include a pass or fail prediction for each cutoff, a step-by-step breakdown of the math, and a chart that shows how your EtG level drops over time. You can also check where your levels may be 24 hours from now. Keep in mind that this tool provides estimates only. Real EtG levels vary based on hydration, metabolism, kidney function, and other factors that no calculator can fully account for. For a related measure of how alcohol affects your body in the short term, you can also try our BAC calculator.

How to Use Our EtG Calculator

Enter details about what you drank, when you drank, and your body size. The calculator will estimate your EtG level at test time, show if you pass or fail common cutoffs (500, 300, and 100 ng/mL), and display a chart of how your EtG drops over time.

Drink Type: Pick beer, wine, or liquor. Each one is set to a standard drink size and alcohol percentage. If you had a craft beer, cocktail, or non-standard pour, turn on "Custom Drink" and type in your exact serving size and ABV%. If you need help figuring out the alcohol content of a homemade brew or fermented drink, our ABV calculator can help you determine the percentage.

Number of Drinks: Use the plus and minus buttons, the slider, or type in how many drinks you had. You can enter any number from 0 to 50. If you are planning how many drinks to serve at an event instead, our drink calculator can help with that.

Hours Spent Drinking: Enter how long your drinking session lasted from your first drink to your last. This is not the time since you stopped — it is the total length of the session.

Hours Until Test: Enter how many hours from right now until you expect to be tested. For example, if your test is tomorrow morning and that is 14 hours away, type 14.

Time Since Last Drink: Enter how many hours ago you had your last drink. You can use the plus and minus buttons to adjust by one hour at a time. If you know the exact moment you stopped drinking, turn on "Use exact time" and pick the date and time instead.

Body Weight: Type your weight in pounds or kilograms. Use the lbs/kg toggle to switch units. The calculator converts automatically when you switch.

Biological Sex: Choose male or female. This sets the Widmark body water ratio used in the formula. Males use 0.68 and females use 0.55. This ratio reflects differences in body composition — if you are curious about yours, tools like a body fat calculator can provide additional context.

Press Calculate to see your results. Press Estimate My EtG Level Tomorrow to see a projection 24 hours from now. Press Reset to clear all fields back to their defaults.

What Is EtG and How Does This Calculator Work?

EtG stands for Ethyl Glucuronide. It is a substance your body makes when it breaks down alcohol. Even after alcohol leaves your blood, EtG stays in your urine for much longer — sometimes up to 80 hours after your last drink. This is why EtG urine tests are widely used in probation, court programs, workplace testing, custody cases, and substance use treatment monitoring. If you are tracking days of sobriety, our sobriety calculator can help you keep count.

This EtG calculator estimates how much EtG may be in your urine at a future test time. You enter what you drank, how much, your body weight, your sex, and when you stopped drinking. The calculator then uses a pharmacokinetic model to estimate your peak EtG level, your EtG level at test time, and how long it takes for EtG to drop below common testing cutoffs. For a quick check of your current blood alcohol concentration rather than the longer-lasting EtG metabolite, see our BAC calculator.

EtG Testing Cutoff Levels

Most EtG urine tests use one of three cutoff levels:

  • 500 ng/mL — The standard cutoff used in most testing programs. A result above this level strongly suggests recent drinking.
  • 300 ng/mL — A sensitive cutoff used in enhanced monitoring programs that want to catch lower levels of use.
  • 100 ng/mL — The strictest cutoff, often used in probation, DOT (Department of Transportation), and custody settings. At this level, even small amounts of alcohol may trigger a positive result.

What Affects EtG Levels?

Several things change how fast your body clears EtG. The amount of alcohol you drank matters most. More drinks means a higher peak EtG level and a longer detection window. You can use our alcohol unit calculator to understand exactly how many standard units of alcohol your drinks contain. Body weight and biological sex also play a role because they affect how your body distributes alcohol. People with lower body weight or a lower Widmark factor (females) tend to produce higher EtG concentrations from the same amount of alcohol.

EtG has a half-life of about 2 to 3 hours in most studies, though this calculator uses a conservative half-life of approximately 9 hours to account for the slower tail-end elimination seen in real-world urine testing. This means EtG levels drop by roughly half every 9 hours during the later clearance phase. If you want to understand how half-life decay works in general, our half life calculator explains and computes the math behind exponential decay.

Important Limitations

This calculator gives estimates only. Real EtG levels vary from person to person based on hydration, kidney function, metabolism, food intake, and other factors the calculator cannot measure. A very hydrated person may produce a lower reading, while a dehydrated person may test higher — our water intake calculator can help you understand your daily hydration needs, though drinking extra water will not reliably "flush" EtG from your system. Certain products like hand sanitizer, mouthwash, and some medications contain alcohol and can cause a positive EtG result even without drinking.

This tool is not medical or legal advice. It is meant for educational purposes. Do not rely on it to make decisions about drug or alcohol testing. If you have concerns about a test, speak with a healthcare provider or your supervising authority. For clinical settings that assess alcohol withdrawal symptoms, the CIWA calculator is a widely used screening tool.

Formulas used

Total Alcohol Consumed
A = n \times V_{\text{mL}} \times \frac{\text{ABV}}{100} \times 0.789
Volume of Distribution (Widmark)
V_d = r \times W_{\text{kg}}
Elimination and Formation Rate Constants
k_e = \frac{\ln 2}{9}, \quad k_a = \frac{\ln 2}{1.5 + 0.35 \times t_{\text{drinking}}}
Peak EtG Concentration
C_{\text{peak}} = 3800 \times \frac{A}{V_d}
Time of Peak (Bateman)
\tau_{\text{peak}} = \frac{\ln(k_a / k_e)}{k_a - k_e}
EtG Concentration at Time τ (Bateman Equation)
\text{EtG}(\tau) = C_0 \left( e^{-k_e \tau} - e^{-k_a \tau} \right), \quad C_0 = \frac{C_{\text{peak}}}{e^{-k_e \tau_{\text{peak}}} - e^{-k_a \tau_{\text{peak}}}}
Tau at Test Time
\tau_{\text{test}} = t_{\text{since}} + t_{\text{until test}}

Frequently asked questions

What is EtG?

EtG stands for ethyl glucuronide. It is a substance your body creates when it processes alcohol. EtG stays in your urine much longer than alcohol stays in your blood. This is why it is used to detect drinking days after it happened.

How accurate is this EtG calculator?

This calculator gives estimates based on a pharmacokinetic model. It is not exact. Real EtG levels depend on your hydration, metabolism, kidney health, food intake, and other personal factors. Use it as a general guide, not a guarantee.

Can I fail an EtG test from hand sanitizer or mouthwash?

Yes. Hand sanitizer, mouthwash, certain medications, and some foods contain alcohol. These can raise your EtG levels enough to trigger a positive result, especially at the strict 100 ng/mL cutoff. This calculator only estimates EtG from drinks you consumed, not from incidental exposure.

What does the Widmark factor mean?

The Widmark factor (r) represents how much of your body weight is water. Males typically have a factor of 0.68 and females 0.55. This matters because alcohol spreads through body water. A lower factor means the same amount of alcohol creates a higher concentration in your body.

What is the difference between time since last drink and hours spent drinking?

Hours spent drinking is the length of your drinking session from first sip to last sip. Time since last drink is how many hours ago you stopped. These are two different numbers. The calculator needs both to estimate your EtG level correctly.

Which EtG cutoff will my test use?

It depends on who ordered the test. Most standard programs use 500 ng/mL. Enhanced monitoring may use 300 ng/mL. Probation, DOT, and custody programs often use the strict 100 ng/mL cutoff. Ask your testing program or supervising officer which cutoff applies to you.

How long does EtG stay in urine?

EtG can be detected in urine for up to 80 hours after your last drink, depending on how much you drank. Light drinking may only show up for 24 to 48 hours. Heavy drinking can produce detectable EtG for 3 days or more.

Will drinking lots of water help me pass an EtG test?

Drinking water may dilute your urine and lower the EtG reading slightly, but it will not flush EtG from your body. Many testing programs also check for overly diluted samples. A dilute result can be treated as a failed test or require a retest.

What does the Estimate My EtG Level Tomorrow button do?

It projects what your EtG level will be exactly 24 hours from now. It shows the estimated concentration and whether you would pass or fail each of the three cutoffs at that time.

What is a standard drink in this calculator?

A standard drink is 12 oz of beer at 5% ABV, 5 oz of wine at 12% ABV, or 1.5 oz of liquor at 40% ABV. Each of these contains roughly the same amount of pure alcohol. If your drink does not match these sizes, use the Custom Drink option.

Why is my peak EtG level so high?

Peak EtG depends on the total amount of alcohol consumed, your body weight, and your biological sex. More drinks, lower body weight, and a lower Widmark factor all lead to a higher peak. The number can seem large, but EtG is measured in nanograms per milliliter, which is a very small unit.

Can one drink cause a positive EtG test?

Yes, especially at the 100 ng/mL cutoff. A single standard drink can produce a positive result for 24 hours or more at that strict level. At the 500 ng/mL cutoff, one drink is less likely to cause a positive result unless the test is taken within a few hours.

What does hours until test mean?

It is the number of hours from right now until you expect to take the test. For example, if your test is tomorrow morning and that is 16 hours away, enter 16. The calculator measures this from the current moment, not from your last drink.

Does body weight affect EtG levels?

Yes. A heavier person has a larger volume of body water, which dilutes the alcohol more. This leads to a lower peak EtG level compared to a lighter person who drank the same amount.

What is the EtG half-life used in this calculator?

This calculator uses a half-life of about 9 hours. This is more conservative than the 2 to 3 hour half-life reported in some studies. The longer value accounts for the slower elimination that happens during the tail end of EtG clearance in real-world urine testing.

Can I use this calculator for an EtG blood test?

No. This calculator is designed for EtG urine tests only. EtG levels in blood are different from urine levels and clear from the body faster. Do not use these results to predict a blood EtG test.

What should I do if the calculator says I will fail?

If the estimate shows a fail, the safest option is to wait longer before testing if possible. Do not rely on this tool to make final decisions. Speak with your supervising authority or a healthcare provider if you have concerns about an upcoming test.

Does the type of alcohol matter for EtG?

The type of drink does not matter by itself. What matters is the total amount of pure alcohol consumed. A glass of wine and a shot of liquor contain roughly the same amount of alcohol and will produce similar EtG levels. The calculator accounts for this using the serving size and ABV of each drink type.

Why does the chart show EtG rising before it falls?

Your body does not create EtG instantly. After you stop drinking, your liver converts alcohol into EtG over a period of time. The EtG level rises as this conversion happens, reaches a peak, and then gradually falls as your body eliminates the EtG through urine.

Can I use this calculator if I drank over multiple days?

This calculator is designed for a single drinking session. If you drank over multiple days, the results will be less accurate. For the best estimate, enter the total drinks and use the time since your very last drink.

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