When should you stop caffeine before bed?
There is no single answer to “will an afternoon coffee keep me up?” — it depends on the dose, the time and the person. Research still gives a useful starting point.
Even six hours before bed
In a 2013 study, people took 400 mg of caffeine (about 2–3 mugs of coffee) 0, 3 or 6 hours before bed. Even caffeine taken six hours before bed cut measured total sleep by more than an hour, and most people didn’t notice. The study was small (12 people) and used a high dose, so it doesn’t transfer to everyone as is.
What 24 studies found together
A 2023 meta-analysis pooled 24 studies. On average caffeine cut total sleep by about 45 minutes and made falling asleep take longer. By the authors’ estimate, to avoid losing sleep time:
- a cup of coffee (≈ 107 mg) should be had at least 8.8 hours before bed,
- a high-caffeine pre-workout serving (≈ 217 mg) at least 13.2 hours before bed.
The authors present these times as a starting point to adjust to the individual.
Applied to your own bedtime
It is easy to apply to your own night: with an 11 PM bedtime, 8.8 hours earlier is around 2:10 PM. That is a study’s average, not a personal rule; it is longer for someone who clears caffeine slowly and shorter for someone fast.
In Caffeine Tracker
Caffeine Tracker doesn’t tell you whether you’ll sleep. It shows an estimate of how much caffeine will be left at your bedtime, and Coffee now? lets you see what a drink would change before you have it.
Sources: Drake et al. 2013, Journal of Clinical Sleep Medicine · AASM release · Gardiner et al. 2023, Sleep Medicine Reviews – summary
See what's still in you now →General information with sources, not medical advice.