Sobering Time Calculator - When Will You Be Sober

You cannot speed it up, but you can plan around it

The liver eliminates alcohol at a fixed rate of 0.10-0.20 per mille per hour (average 0.15). Coffee, cold showers, energy drinks, vomiting, exercise - none of these change the rate. The only variable you control is how much you drink. This calculator takes your current blood alcohol level - either from a breathalyzer reading or calculated from your drinks - and builds an hour-by-hour countdown to zero.

Two input modes: enter what you drank (type, amount, time since last drink) and the calculator computes your current BAC using the Widmark formula. Or enter a breathalyzer reading directly for maximum accuracy. Either way, the output is the same: when you hit zero, and when you cross each legal driving limit.

How to use this calculator - step by step

Select your sex - women have a lower Widmark factor (0.55 vs 0.68), so sobering takes longer at the same BAC.
Enter your weight - heavier people dilute alcohol more, reaching lower BAC from the same drinks.
Choose input method - "what I drank" uses the Widmark formula to calculate BAC. "Breathalyzer reading" skips the calculation and uses your measured value.
Enter drink details or BAC - if using drinks: select type, enter volume in ml. If using breathalyzer: enter the per mille reading.
Enter hours since last drink - optional. Accounts for alcohol already eliminated. Leave at 0 if still drinking.
Read your timeline - the table shows BAC at each hour, with clock times and legal limit status.

Elimination rate - what affects it

Factor	Effect on rate	Details
Regular drinkers	Faster (0.15-0.20)	Liver enzymes upregulated from chronic exposure. Not a health benefit.
Occasional drinkers	Slower (0.10-0.15)	Lower enzyme activity means slower processing.
Food in stomach	No effect on rate	Slows absorption (lower peak), but does not change elimination speed.
Liver disease	Much slower	Damaged liver = fewer working enzymes = longer sobering time.
Medications	Varies	Some drugs inhibit ADH (slower). Others compete for the same enzymes.
Coffee, exercise, showers	Zero effect	May make you feel more alert, but BAC stays the same. Only time works.

Real-world sobering scenarios

Male, 80 kg, 3 beers (500 ml each, 5%), stopped 1 hour ago
Peak BAC: 1.09 per mille. Current: 0.94. Fully sober in: ~6 h 15 min. Below 0.05% in: ~3 h. Below 0.08% in: ~1 h.

Female, 60 kg, bottle of wine (750 ml, 12%), stopped 2 hours ago
Peak BAC: 2.15 per mille. Current: 1.85. Fully sober in: ~12 h 20 min. Morning drinking = afternoon driver at best.

Breathalyzer reading: 0.85 per mille (male, 90 kg)
Sober in: ~5 h 40 min. Below 0.05% in: ~2 h 20 min. Below 0.08% in: ~20 min.

Male, 75 kg, 4 shots vodka (40 ml each, 40%), stopped 3 hours ago
Peak BAC: 0.99 per mille. Current: 0.54. Sober in: ~3 h 35 min. The 3 hours already eliminated 0.45 per mille.

Female, 55 kg, 2 glasses of wine (150 ml each, 12%), just finished
Peak BAC: 0.94 per mille. Sober in: ~6 h 15 min. Even two standard glasses push a lighter woman well above all driving limits.

Frequently asked questions

Can I sober up faster?

No. The liver metabolizes alcohol via alcohol dehydrogenase (ADH) at a rate governed by enzyme kinetics. This rate is 0.10-0.20 per mille per hour and cannot be increased by any home remedy. Coffee makes you a wide-awake drunk. Cold showers make you a cold, wet drunk. Exercise makes you a sweaty drunk. Only time reduces BAC.

Why does it matter whether I ate before drinking?

Food slows alcohol absorption, not elimination. A full stomach delays alcohol reaching the small intestine, so your peak BAC is lower and arrives later. But the total amount absorbed stays the same, and the elimination rate does not change. The practical effect: eating before drinking makes the BAC curve flatter but not shorter. You still need the same number of hours to reach zero.

Is "sleeping it off" a myth?

Partly. Sleep does not speed up elimination, but it does give the process uninterrupted time. If you pass out at 1.5 per mille and sleep 8 hours, you will wake up at roughly 0.3 per mille (1.5 - 8 x 0.15 = 0.3). Many morning-after DUI arrests happen because people underestimate how much alcohol is still in their system after a "full night's sleep" that was actually only 5-6 hours.

How does body weight affect sobering time?

Weight affects peak BAC (heavier = lower BAC from the same drinks) but not the elimination rate. A 100 kg man and a 60 kg man who both reach 1.0 per mille will sober up in the same time (~6.5 hours). The difference is that the 100 kg man needed more alcohol to reach that level. Weight makes the starting point lower, not the clock faster.

What is the difference between per mille and % BAC?

Per mille = parts per thousand. Percent = parts per hundred. Divide per mille by 10 to get percent: 0.8 per mille = 0.08% BAC. The US legal limit of 0.08% equals 0.8 per mille. Most of Europe uses per mille with limits of 0.2-0.5. The calculator shows both units in the timeline table.

How accurate is this calculator?

If you entered a breathalyzer reading, the elimination timeline is accurate to within +/- 1 hour (since the elimination rate varies 0.10-0.20). If you entered drinks, the initial BAC estimate adds another +/- 15-20% uncertainty from the Widmark formula. For safety, always add a buffer of 1-2 hours beyond what the calculator shows.

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