Caffeine Half-Life Bedtime Calculator
Enter today's drinks and your bedtime to see how much caffeine stays in your body at bedtime and your sleep-disruption risk.
☕ Drinks Today
each 125mg
each 125mg
Healthy adults avg ~5 hours (varies with pregnancy, medication, liver function)
Daily limit
📊 Bedtime Caffeine Result
Total caffeine
250 mg
Residual at bedtime
55 mg
at 23:30
Sleep-disruption risk🟡 Caution
Some caffeine remains at bedtime; you may find it harder to fall asleep.
Caffeine decay curve
Drops to 50mg
⏰ 00:13
43분 after bedtime
Last safe intake time
🚫 16:53
For one standard Americano (125mg) to stay ≤50mg at bedtime
👍 Within daily limit (250 mg / 400mg)
Data sources
- ☕ Beverage caffeine: Korea MFDS coffee-shop survey + manufacturer labels
- ⏳ Half-life: healthy-adult average ~5 hours (EFSA / clinical data)
- 📏 Daily limit: Korea MFDS adult 400mg / pregnant 300mg
- 😴 Sleep effects: Drake et al. (2013) J Clin Sleep Med
※ All figures are reference estimates based on averages; actual caffeine metabolism and sleep response vary widely by individual.
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