Guide
How Long Does It Take for Alcohol to Leave Your Body?
"I drank last night — can I drive this morning?" only has one honest answer, and it is arithmetic. Alcohol leaves the body at a fixed and surprisingly slow rate, and neither coffee nor a cold shower nor exercise changes that rate. This article explains how alcohol is cleared, how long it takes, and how to estimate it roughly for yourself.
How your body processes alcohol
Roughly 90-95% of the alcohol you drink is broken down enzymatically in the liver. The small remainder leaves unchanged through breath, sweat and urine — and that breath fraction is exactly what a breathalyser measures.
The liver process runs in two steps. First, alcohol dehydrogenase (ADH) converts ethanol into acetaldehyde, a toxic intermediate largely responsible for the headache and nausea of a hangover. Then aldehyde dehydrogenase (ALDH) turns acetaldehyde into harmless acetate, which is eventually broken down to carbon dioxide and water.
The critical point is that these enzymes saturate. They cannot work faster than a certain rate. No matter how much you drink, the liver processes alcohol at a steady pace and the excess simply waits in your bloodstream. This is why alcohol follows what is called zero-order kinetics — a fixed amount per hour, regardless of dose.
How many per mille per hour?
In a healthy adult the liver lowers blood alcohol concentration by roughly 0.12‰ to 0.15‰ per hour. Promil Tracker's calculations use the upper end of that range, 0.15‰ per hour.
The rate varies between people. In heavy, regular drinkers liver enzyme activity can increase and elimination may reach 0.20-0.25‰ per hour. Treating that as an advantage is a serious mistake: faster metabolism means the liver is under more strain and accumulating more damage. Conversely, people with liver disease or on certain medications can clear alcohol considerably more slowly.
- Typical elimination: 0.12-0.15‰ per hour
- Heavy drinkers: up to 0.20-0.25‰ per hour (not a good sign for your health)
- Impaired liver function: markedly slower
Worked examples
A simple rule of thumb: divide your current BAC by 0.15 to get a rough number of hours until it reaches zero.
All of these figures describe what happens after you have reached peak BAC. If you have only just finished your last drink, absorption may still be underway — meaning your BAC will keep climbing for a while before the decline begins.
- At 0.30‰: about 2 hours
- At 0.50‰ (the passenger-car limit in Turkey): about 3.5 hours
- At 0.80‰: about 5.5 hours
- At 1.20‰: about 8 hours
Can you still be over the limit the next morning?
Yes, and it happens far more often than people assume. Someone who drank heavily past midnight can still be over the legal limit on the morning commute.
Consider an 80 kg person who peaked at 1.50‰ at 2 a.m. Declining at 0.15‰ per hour, they are still at roughly 0.60‰ at 8 a.m. — above Turkey's 0.50‰ passenger-car limit. Feeling fine changes nothing; the device measures the alcohol in your blood, not how alert you feel.
This is the clearest illustration of why "I slept it off" is a dangerous assumption. Sleep does not remove alcohol, it only passes time — and usually not enough of it.
Sobering-up methods that do not work
None of the folk remedies for sobering up lower your blood alcohol concentration. Some of them make you feel more awake, which is a dangerous illusion — feeling alert is not the same as having your reflexes and judgement back.
Coffee is the classic example: caffeine suppresses drowsiness but does nothing for coordination, reaction time or decision-making. The result is a driver who believes they are fit to drive while being just as impaired as before.
- Coffee — creates alertness only, does not lower BAC
- Cold showers — affect circulation, not alcohol metabolism
- Exercise or sweating — the amount of alcohol excreted is negligible
- Drinking lots of water — helps with dehydration, not with BAC
- Vomiting — may remove what is still in the stomach, but has no effect on alcohol already absorbed
- A heavy meal — slows absorption, so it only helps BEFORE you drink
The only thing that works is time
There is no reliable intervention that speeds up alcohol elimination. The liver works at its own pace and you do not get to choose that pace. The only available option is waiting for your BAC to fall naturally.
The practical takeaway is to decide how you are getting home before you start drinking. If you are driving, do not drink; if you are drinking, leave the car. Calculators are useful for planning, but they should never be used to shave the legal limit.
Frequently Asked Questions
Breath and blood tests measure current alcohol, so once your BAC reaches zero the result is clean — typically 6-12 hours after the last drink. Urine tests, especially those looking for the EtG metabolite, can stay positive for 24-72 hours because they detect residual by-products rather than alcohol itself.
No. Body mass lowers the peak BAC reached from the same amount of alcohol, because the alcohol distributes into a larger volume of body water. But the per-hour decline is set by liver capacity, which does not scale directly with weight.
Because two separate variables are at play: the starting BAC, which depends on weight, sex, body composition and stomach contents, and the elimination rate, which depends on liver capacity. Even if two people reach the same BAC, different liver rates mean different sobering times.
Because absorption and elimination are two separate processes running at once. After your last sip there is still unabsorbed alcohol in your stomach and intestine. Peak BAC is usually reached 30-90 minutes after the final drink; only then does the decline start.