Free sobriety calculator
See how long until you're sober in two seconds. Enter your current BAC and this sobriety calculator divides it by the average elimination rate of 0.015 BAC per hour to return the hours until your blood alcohol content reaches zero — with a time-to-sober-by-BAC chart and why nothing speeds it up. An estimate of the minimum time, never a green light to drive — updated live, as you type.
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Average metabolic rate 0.015% BAC/hour. Individual rates vary. Never drive until you are certain you are sober — when in doubt, don't drive.
Results are estimates. Consult a professional.
What is sobriety time?
Sobriety time is how long it takes your body to clear all the alcohol from your blood — the number of hours until your blood alcohol content (BAC) falls back to zero. It is the question behind "when will I be sober?" and "how long until I can drive?", and it is the figure this sobriety calculator returns the moment you enter your current BAC.
Your liver breaks alcohol down at a roughly steady pace — on average about 0.015 BAC per hour. So the time to reach zero is simply your current BAC divided by that rate. A BAC of 0.08% takes a little over 5 hours to clear; a 0.15% takes about 10. The higher you start, the longer the wait, and there is no way to rush it.
How the sobriety calculator works
The calculator takes one input — your current BAC — and divides it by the average rate at which the liver eliminates alcohol, 0.015 BAC per hour. The result is the number of hours until your BAC reaches zero.
The one thing you need first is your current BAC, and most people do not know it off the top of their head. Estimate it from your drinks, body weight, and sex with the BAC calculator, then bring that number here to see how long it takes to clear. In short: the BAC calculator tells you the level you are at now; this calculator tells you how long until it is gone.
How long does alcohol take to leave your system?
Once alcohol is in your bloodstream, only time removes it. The liver processes more than 90% of the alcohol you drink, breaking it down at a fixed pace that does not speed up no matter how much you have had — chemists call this zero-order kinetics. That steady pace averages about 0.015 BAC per hour, roughly the amount in one standard drink.
Because the rate is constant, the maths is simple and unforgiving: double your BAC and you double the wait. A person at 0.05% is clear in about 3 hours 20 minutes; at 0.08% it is over 5 hours; at 0.15% it is 10 hours. The liver cannot be hurried, so the only lever you control is how high you let your BAC climb in the first place.
A worked example using the sobriety calculator
Someone has been drinking and estimates their current BAC at 0.08% — the US legal driving limit. They want to know how long until they are completely sober. Here is the arithmetic the calculator runs.
Step 1 — Start with your current BAC
Enter the BAC you are starting from. Here it is 0.08. If you do not know it, estimate it first with the BAC calculator from your drinks, weight, and sex.
Step 2 — Divide by the elimination rate
The liver clears about 0.015 BAC per hour, so divide your starting BAC by that rate: 0.08 ÷ 0.015 = 5.3.
Step 3 — Read the time to zero
How long to sober up by BAC level
Because alcohol clears at a flat 0.015 BAC per hour, the time to reach zero is fixed by your starting BAC alone. The table below applies the formula directly across common BAC levels — the same numbers the calculator returns.
| Starting BAC | Approx. time to reach zero |
|---|---|
| 0.02% | ~1.3 hours |
| 0.05% | ~3.3 hours |
| 0.08% (US driving limit) | ~5.3 hours |
| 0.10% | ~6.7 hours |
| 0.15% | ~10 hours |
| 0.20% | ~13.3 hours |
| 0.25% | ~16.7 hours |
| 0.30% | ~20 hours |
Time = BAC ÷ 0.015 per hour. Average estimates; individual elimination rates vary.
How long to sober up by number of drinks
Estimating sobriety time from a drink count is a two-step process, because the calculator works from BAC, not drinks. First turn your drinks into an estimated BAC; then divide that BAC by 0.015 to get the hours to zero.
- Estimate your BAC from the drinks. The same number of drinks lands at very different BACs depending on body weight, sex, pace, and food — so this step belongs to the BAC calculator, which applies the Widmark formula. As a rough anchor, about 4 standard drinks in 2 hours brings an average 80 kg man near 0.08%.
- Divide that BAC by the elimination rate. Bring the estimated BAC here and divide by 0.015 to get the hours until it reaches zero. At 0.08%, that is about 5.3 hours.
A simpler field rule the NIAAA suggests is to allow at least one hour per standard drink — and then some, because that ignores the BAC you have already built up. The two-step BAC method is more honest, but neither is precise enough to base a decision to drive on.
Why you can't speed up sobering up
Every popular trick for sobering up faster is a myth. Coffee, a cold shower, a big meal, water, exercise, fresh air, or making yourself sick do not lower your BAC. Your liver removes alcohol at its own fixed pace, and nothing you do from the outside changes that pace.
- Coffee makes you feel more awake but does nothing to your BAC — it produces a wide-awake drunk, which is more dangerous, not less.
- A cold shower is a jolt, not a treatment; you end up alert and still impaired.
- Food eaten before drinking slows how fast alcohol is absorbed, lowering the peak — but once alcohol is in your blood, food cannot clear it.
- Sleep does not speed elimination either. You wake feeling better while your BAC has only fallen by the same 0.015 per hour it would have anyway.
Can you drive the morning after drinking?
Often not — and this is where the steady elimination rate catches people out. If you finish a heavy night at a BAC of 0.16%, the calculator says about 10.7 hours to reach zero. Stop drinking at 2 a.m. and you are not reliably clear until roughly 1 p.m. the next day, and you can still be over the 0.08% driving limit when you wake at 8 a.m.
Sleep is the trap. A good night's rest makes you feel rested and alert, but it does not speed elimination — your BAC falls at the same 0.015 per hour whether you are awake or asleep. Drivers fitted with ignition interlocks are routinely surprised to fail their first breath test of the morning while feeling completely sober. This is the classic morning-after DUI: legally impaired, but convinced you are fine.
Limitations: why this is an estimate, never a green light to drive
This calculator is an educational estimate of the minimum time to sober up, not a measurement. It uses a single average elimination rate and assumes you have already reached your peak BAC — and in the real world several things push the true time longer.
- It uses a flat 0.015 BAC/hour rate. Real elimination varies between people, and a slower metabolism means a longer wait than shown.
- It assumes absorption is finished. If you drank recently, alcohol may still be entering your blood — your BAC can keep rising for 30–90 minutes after your last drink, so the clock to zero starts later than you think.
- It is only as good as the starting BAC you enter, which is itself an estimate from the BAC calculator — errors there carry straight through.
- It is not a breathalyser and has no legal standing. Only a tested measurement reflects your real BAC.
Data sources and methodology
The estimate divides your current BAC by an average alcohol elimination rate of 0.015 BAC per hour — the widely cited population average used by US health and traffic-safety agencies, and the same rate the BAC calculator subtracts over time. The morning-after and "nothing speeds it up" guidance follows US National Highway Traffic Safety Administration (NHTSA) and NIAAA information on alcohol metabolism.
US NHTSA — drunk driving; US NIAAA — alcohol metabolism and standard drink information.Frequently asked questions about the free sobriety calculator
About this sobriety calculator
This sobriety calculator runs entirely in your browser. The BAC you type never leaves your device — nothing is sent to a server, logged, or shared. It divides your current blood alcohol content by an average elimination rate of 0.015 BAC per hour, updating instantly as you type. It estimates the minimum time until your BAC reaches zero — an educational estimate, not a measurement, and never a basis for deciding to drive.
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