How long does alcohol stay in your system?
There's no single answer — it depends on what's being measured. Alcohol clears the blood in hours, but the traces it leaves behind can be picked up for days. Here's the honest breakdown across every common test.
The short version
Once you stop drinking, your body gets to work removing alcohol at a steady, fixed pace. As a rough guide, the alcohol itself is gone from your bloodstream within about 6 to 12 hours. But different tests look for different things, so the "how long" changes depending on who's asking and why:
| Test type | Typical detection window |
|---|---|
| Blood | Up to ~12 hours |
| Breath (breathalyser) | ~12–24 hours |
| Saliva | ~12–24 hours |
| Urine — standard | ~12–24 hours |
| Urine — EtG test | Up to ~2–4 days (48–80 hours) |
| Hair | Up to ~90 days (heavy, long-term use) |
These are general ranges. The exact window depends on how much you drank, how quickly, your body composition, your liver health and the sensitivity of the test itself.
How your body processes alcohol
After you drink, alcohol is absorbed through the stomach and small intestine into your bloodstream. From there, your liver does the heavy lifting — it breaks down roughly 90% of the alcohol you consume. The small remainder leaves through your breath, sweat and urine, which is exactly why breath and urine tests work.
Crucially, the liver works at a fixed rate: about one standard drink (10 g of alcohol) per hour. That lowers your blood alcohol content (BAC) by roughly 0.015% each hour. Drink faster than your liver can process and alcohol banks up in your blood, pushing your BAC higher. Once you stop, only time brings it back down.
Detection windows, test by test
Blood tests
A blood test measures the actual concentration of alcohol in your bloodstream, so it tracks your real-time BAC closely. Because your liver is steadily clearing it, alcohol usually drops below detectable levels within about 6 to 12 hours of your last drink. Blood tests are the most direct measure but also the most invasive, so they're mostly used in hospitals and serious legal cases.
Breath tests
The breathalyser used in random breath testing estimates your BAC from the alcohol in the air you exhale. It reflects recent drinking and is generally useful for around 12 to 24 hours after your last drink, depending on how much you had. This is the test most Australian drivers will ever encounter — and it's why a big night out can still catch you out at a morning roadside stop.
Saliva tests
Saliva (oral fluid) tests are quick and non-invasive, often used for workplace or roadside screening. Their window roughly mirrors the breath test — up to about 12 to 24 hours — because they, too, are detecting alcohol that's still circulating rather than a longer-lasting metabolite.
Urine tests
There are two very different urine tests. A standard urine test looks for alcohol itself and typically detects it for around 12 to 24 hours. The EtG test is a different beast: it looks for ethyl glucuronide, a by-product produced when the body processes alcohol. EtG lingers well after the alcohol is gone, which is why the EtG test can pick up drinking from up to 2 to 4 days earlier. That sensitivity makes it popular for abstinence monitoring — but it can also flag very small exposures, so results are read with care.
Hair tests
Hair testing doesn't catch a single big night. Instead, it reveals patterns of heavy, sustained drinking over an extended period — potentially up to about 90 days back, depending on hair length. It's used in some clinical, legal and custody contexts rather than for everyday screening.
What doesn't speed things up
Plenty of "quick fixes" get passed around, and none of them actually remove absorbed alcohol from your system any faster:
- Coffee and energy drinks — caffeine makes you feel more alert but doesn't change how much alcohol is in your blood.
- Cold showers — you'll be wide awake and exactly as affected as before.
- Exercise and sweating — only a small fraction of alcohol leaves through sweat, so "sweating it out" barely moves the needle.
- Vomiting — only clears alcohol still sitting in your stomach; anything already absorbed stays put.
- Water — staying hydrated helps you feel better and eases a hangover, but it won't dilute your BAC or beat a test.
The only thing that genuinely reduces the alcohol in your system is time. Everything else just changes how you feel, not the numbers a test will read.
What changes your personal timeline
Two people can drink the same amount and clear it at noticeably different rates. The main factors:
- How much and how fast — more alcohol takes proportionally longer to clear.
- Body size and composition — alcohol distributes through body water, so a larger or leaner body tends to reach a lower peak BAC.
- Sex — people assigned female at birth generally have less body water and less of the enzyme that breaks alcohol down, so they often process it more slowly.
- Food — eating before or while drinking slows absorption and lowers your peak, though it doesn't change how fast alcohol leaves once it's in your blood.
- Liver health and medication — liver damage and some medicines slow the whole process down.
Frequently asked questions
How long does alcohol stay in your system?
It depends on the test. Alcohol leaves the blood within about 6 to 12 hours and shows on breath or saliva for roughly 12 to 24 hours. The EtG urine test can find traces for up to 2 to 4 days, and a hair test can reflect heavy long-term drinking for up to about 90 days.
How long does it take to process one standard drink?
About an hour, on average. One standard drink is 10 g of alcohol, and your liver clears roughly that much per hour — lowering your BAC by around 0.015% each hour. The rate varies from person to person and can't be rushed.
Can you speed up how fast alcohol leaves your body?
No. Coffee, cold showers, exercise, sweating and vomiting don't remove absorbed alcohol any faster. Only time lowers the amount in your system.
Will alcohol show up on a drug test?
Standard drug panels usually don't include alcohol, but a specific alcohol test can be ordered. A breath or standard urine test catches recent drinking, while an EtG urine test can detect drinking from the past few days.
Does a positive test mean I'm still drunk?
Not necessarily. A test — especially an EtG test — can detect alcohol or its by-products long after you feel sober and after your BAC has returned to zero. Detection isn't the same as impairment.
Sources: Alcohol and Drug Foundation — Blood Alcohol Concentration, Alcohol and Drug Foundation — Alcohol facts, and Cleveland Clinic — How Long Does Alcohol Stay in Your System?