How Long Does Alcohol Stay in Your System?

If you've typed how long does alcohol stay in your system into a search bar — maybe before a morning drive, maybe with a test on your mind, maybe just to settle a worry that's been nagging at you — I want to give you a straight answer, with no scaremongering and no lecture. I sit with people every week who've asked almost exactly that question, so I understand the unease behind it. Let me set out what's actually known, and then, gently, one other thing worth saying.

The short, honest answer is that your body clears alcohol at a fairly steady pace, but the traces it leaves behind can be picked up for far longer than the buzz lasts. Roughly speaking, a healthy liver processes about one unit of alcohol an hour — that's around a single small measure of spirits, half a pint of ordinary-strength beer, or a small glass of wine. So the more you drink, the longer it takes to clear, and it adds up in a line rather than vanishing all at once. The figures below are rough guides, not guarantees. Anyone who hands you an exact number is guessing.

How long does alcohol stay in your system, by test type

Different tests look in different places and over very different timeframes. Here's the realistic picture for each.

• Breath. A breathalyser measures alcohol on your breath in real time, so it tracks roughly with how much is still in your blood — usually detectable for several hours after drinking, depending on how much you had.
• Blood. Alcohol itself generally shows in blood for around 6 to 12 hours after your last drink, though heavy drinking pushes that out further.
• Urine (standard). A basic urine test for alcohol itself catches it for roughly 12 to 24 hours.
• Urine (EtG/EtS). These tests look for ethyl glucuronide and ethyl sulfate — by-products that linger long after the alcohol has gone. They can flag drinking for around up to 48 to 72 hours, and sometimes longer after heavy use, which is why they're used where abstinence really matters.
• Hair. Hair testing has by far the longest reach — markers can show patterns of drinking over a period of months, because traces lock into the hair as it grows.

Why the only reliable thing that clears alcohol is time

This trips a lot of people up, so it's worth being plain about it. Your liver does almost all the work of breaking alcohol down, and it does it at its own steady rate that you can't really hurry. Coffee, a cold shower, a big breakfast, sweating it out at the gym, or downing pints of water — none of these reliably speed up clearance, and none of them will reliably fool a test. You might feel a bit fresher, but the alcohol is still leaving your body at the same unhurried pace. To put rough numbers on it, here's how a few sittings tend to play out.

• Two units (say, a pint of regular beer) — roughly two hours to clear.
• A few large glasses of wine — commonly six hours or more, easily into the next morning.
• A heavy night out — often still detectable well into the following day, and on an EtG test, longer again.

If you want to estimate your own rough window for any substance, our drug detection calculator walks you through the main factors. Just remember it's an estimate, not a promise.

What affects how long alcohol stays in your system

This is where the ranges come from. The same few drinks behave differently from one person to the next, and from one occasion to the next, because of factors like these:

• How much you drank. More units means a longer clearance time, and it stacks up rather than averaging out.
• How fast you drank it. Several drinks in quick succession overwhelm the liver, so they sit in your system longer than the same amount spread over an evening.
• Your body size and composition. A bigger body with more water tends to dilute alcohol more than a smaller one, which affects the peak and the clearance.
• Whether you'd eaten. Food slows how fast alcohol is absorbed, which changes the curve.
• Your liver health and general metabolism. The liver does the heavy lifting; if it isn't working at full tilt, or your metabolism is naturally slower, clearance slows with it.
• Sex, age and medication. All of these shift how alcohol is processed and how long traces hang around.

Put together, those variables are why I can give you a measured range but never a promise. If your drinking has crept up to the point where you're often counting these hours, that pattern is worth a closer look — you'll find an honest, non-judgemental rundown on the alcohol addiction guide.

The more useful question

I'll be honest with you about one thing, because it's the part that actually matters. I'm not going to offer any advice on passing or beating a test, or on flushing alcohol out faster — that's not what this page is for, and it never solves the thing underneath. If you've landed here, I'd gently turn the question around.

When someone is counting the hours until the drink is out of their system, that sum is rarely just admin. It usually carries a quiet weight: will this show, can I get away with it, how close am I cutting it? Plenty of capable, high-functioning people live with that low-level arithmetic running in the background for years. Doing the maths now and then doesn't make you an addict. But if you notice you're doing it often — repeatedly planning around tests, around drives, around hiding how much you've had — that pattern is worth listening to.

The detection window tells you how long alcohol stays in your body. The more useful question is what it's costing you while it's there — and whether you'd genuinely choose this if no test ever existed.

That's not a verdict, and nothing here is a diagnosis. It's an invitation to be honest with yourself for a moment. If something in that landed, two calmer next steps are worth a look. To weigh up where the line actually sits, our guide Am I an Addict? is a gentle place to start, and if cutting down or stopping is on your mind, please read about alcohol withdrawal symptoms first — stopping heavy drinking abruptly can occasionally be dangerous, so it's worth knowing what to expect and when to get medical support.

Whatever brought you here, please know there's no judgement in it. I've sat exactly where you might be sitting now, doing the same mental sums. Asking the honest question — not "how long until it's gone?" but "do I actually want to keep doing this?" — was the start of everything changing for me, and I've watched it be the start for a lot of people who were sure it never could be.

Gary Clinton

Ireland's addiction specialist — CBT-qualified therapist, bestselling author of Never Give Up, and an ex-addict himself. Private one-to-one help for professionals, online and worldwide.