CortexLit

CortexLit tool · Caffeine · Runs offline · No account

Caffeine Cut-Off From Bedtime

Turn your bedtime and a buffer into a clock time, and show what a late drink costs you against the trial's six-hour test.

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This tool gives general information based on the research summarised in How Much Caffeine Is Actually in Your Drink. It is not a medical device, does not diagnose, and does not replace advice from your clinician.

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Free (this page)
  • cut-off time from your bedtime
  • comparison with today's last drink
  • text export and print
  • all citations and cautions


Plus (optional, one-time)
  • calendar (.ics) daily cut-off reminders
  • unlimited share images
  • share card without the 'Made with CortexLit' footer


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Free tier: 1 share image per result.






Commercial disclosure: optional paid Plus tier; all evidence, cautions and the main result are free. No affiliate links, no sponsors.







What this is based on


Every output names at least one verified PubMed source. Identifiers were verified on 2026-10-11 in an earlier batch and carried over into this build; they were not re-queried here, and no retraction database was checked. Verification was at abstract level.


Drake 2013
Drake C, Roehrs T, Shambroom J, Roth T. Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed. J Clin Sleep Med. 2013;9(11):1195-1200.
PMID 24235903 · randomized controlled trial · weight 0.8 · abstract level
Gardiner 2023
Gardiner C, Weakley J, Burke LM, et al. The effect of caffeine on subsequent sleep: A systematic review and meta-analysis. Sleep Med Rev. 2023;69:101764.
PMID 36870101 · systematic review meta analysis · weight 1.0 · abstract level


Limits: The trial used a 400 mg dose in healthy adults; individual caffeine clearance varies widely, so a personal cut-off needs two weeks of your own sleep to judge. This tool computes a clock time, it does not predict sleep.







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