What Time Should You Stop Drinking Coffee?
Most people have no idea how late is too late for their last coffee of the day. The answer depends on your bedtime, your metabolism speed and how much caffeine you want in your system when you go to sleep. This guide gives you the exact science behind caffeine cutoff times and how to find your personal ideal time.
The Simple Rule: Stop 10 Hours Before Bed
With an average caffeine half-life of 5 hours, stopping caffeine at least 10 hours before bed allows your body to eliminate most of the caffeine before you sleep. This means if you go to bed at 10pm your last coffee should be no later than 12pm noon.
| Bedtime | Last Coffee By |
|---|---|
| 9:00 PM | 11:00 AM |
| 10:00 PM | 12:00 PM noon |
| 11:00 PM | 1:00 PM |
| 12:00 AM | 2:00 PM |
| 1:00 AM | 3:00 PM |
Why 10 Hours?
Caffeine has an average half-life of 5 hours in healthy adults. This means every 5 hours your body eliminates half the caffeine. After 10 hours only 25 percent of the original caffeine remains. After 15 hours only 12.5 percent remains.
A 2013 study by Drake et al. published in the Journal of Clinical Sleep Medicine found that caffeine consumed 6 hours before bedtime still significantly disrupted sleep. This confirms that the popular advice of stopping caffeine at 6pm is not sufficient for most people with a 10-11pm bedtime.
Your Cutoff Time Based On Metabolism
Not everyone metabolizes caffeine at the same rate. Your personal caffeine cutoff time depends on your metabolism speed which is determined primarily by your CYP1A2 enzyme genetics.
| Metabolism | Half-Life | Stop Before Bed By |
|---|---|---|
| Fast | 3 hours | 6 hours before |
| Average | 5 hours | 10 hours before |
| Slow | 8 hours | 14 hours before |
| Pregnant | 12 hours | 18 hours before |
What Happens If You Drink Coffee Too Late?
Even if you fall asleep easily after an evening coffee your sleep quality is being compromised. EEG brain studies show that caffeine reduces slow wave deep sleep — the most restorative stage of sleep — even in people who feel completely unaffected by caffeine.
The effects include:
- Reduced total sleep time by up to 1 hour
- Less deep sleep and slow wave sleep
- More nighttime awakenings
- Feeling less rested in the morning
- Reduced next day cognitive performance
Tips To Move Your Caffeine Cutoff Earlier
If you currently drink coffee in the afternoon or evening here are practical ways to move your cutoff earlier without suffering through the day:
- Replace afternoon coffee with green tea which has less caffeine (28mg vs 96mg)
- Gradually move your last coffee 30 minutes earlier each week
- Try decaf in the afternoon — still has the ritual without the caffeine
- Drink water or herbal tea after your cutoff time
- Use our calculator to see the real impact of moving your cutoff earlier
Calculate Your Personal Caffeine Level
Use our free caffeine half-life calculator to see exactly how much caffeine is in your system right now and how it will affect your sleep tonight.
Try The Free Calculator →Frequently Asked Questions
What is the best time to stop drinking coffee?▼
For most people with an average metabolism and a 10pm bedtime the ideal cutoff is 12pm noon. This gives caffeine 10 hours to clear your system to minimal levels before sleep.
Can I drink coffee at 3pm and still sleep well?▼
It depends on your bedtime. If you sleep at 1am a 3pm coffee gives 10 hours for caffeine to clear. If you sleep at 10pm a 3pm coffee only gives 7 hours — likely still disrupting your sleep.
Does decaf affect sleep?▼
Decaf still contains 5-15mg of caffeine per cup. For most people this is negligible but sensitive individuals or pregnant women should be aware of this.
What if I am a slow caffeine metabolizer?▼
Slow metabolizers with an 8 hour half-life should stop caffeine 14-16 hours before bed. For a 10pm bedtime this means stopping by 6-8am in the morning.
Sources
- Drake et al. (2013). Caffeine Effects on Sleep. Journal of Clinical Sleep Medicine
- Walker, M. (2017). Why We Sleep. UC Berkeley
- NIH — Caffeine and Sleep Research