How long does alcohol stay in your system?

Alcohol is metabolized at a relatively consistent rate, but detection depends heavily on which test is used. Standard breath and blood tests have short windows, while newer urine tests can detect alcohol use for days.

Detection by test type

Breathalyzer detects alcohol for 12-24 hours after last drink. Blood testing detects alcohol for 6-12 hours. Standard urine test detects alcohol for 12-24 hours. EtG urine test (ethyl glucuronide) detects alcohol metabolites for 48-80 hours — this is the test used in treatment programs and legal monitoring. Hair follicle testing can detect alcohol use for up to 90 days. Saliva testing detects alcohol for 12-24 hours.

How alcohol is metabolized

The liver processes alcohol at a fairly constant rate of approximately 0.015 BAC per hour — roughly one standard drink per hour. A standard drink is 12 oz beer (5% ABV), 5 oz wine (12% ABV), or 1.5 oz liquor (40% ABV). If you drink faster than your liver can process, your BAC rises. Nothing speeds up this process — not coffee, not food, not cold showers, not exercise. These may make you feel more alert, but your BAC decreases at the same rate regardless.

The EtG test: Why it matters

EtG (ethyl glucuronide) testing has changed alcohol monitoring. Unlike standard alcohol tests that detect ethanol directly (short window), EtG detects a metabolite that remains in urine for 2-3 days after drinking. This is the test used by treatment programs, drug courts, professional monitoring programs, and probation/parole. It is sensitive enough to detect a single drink consumed 48 hours prior. Some hand sanitizers, mouthwashes, and foods containing trace alcohol can cause false positives — inform your monitoring program about any non-beverage alcohol exposure.

When to seek help

If you are tracking how long alcohol stays in your system because you need to pass a test and cannot stop drinking long enough to do so, that pattern itself suggests a problem worth addressing. Read our guide to high-functioning alcoholism or take our free substance use screening.

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Authoritative sources

This article references guidelines from: NIDA · SAMHSA · CDC · FDA · ASAM

Frequently asked questions

Disclaimer: Informational only. Not medical advice. SAMHSA: 1-800-662-4357.