Caffeine at Bedtime Calculator
Add what you drank and when. See how much caffeine is still in your system when you go to bed, and the latest time you can have another cup.
1. What did you drink?
Tap a drink to add it, then set the time. Amounts are typical averages; brands vary, so edit the mg if you know it.
Nothing added yet.
2. When do you go to bed?
3. How fast does your body clear caffeine?
The average half-life is about 5 hours, which means half is gone in 5 hours. It varies a lot between people.
Some medications, such as fluvoxamine, can slow caffeine clearance a lot. Ask your prescriber or pharmacist if you’re unsure.
Your results
Add a drink above to see your results.
Good to know
Why this matters
Caffeine blocks the signal that builds up sleep pressure. Studies show that caffeine taken even 6 hours before bed can shorten sleep and lighten it, even if you fall asleep fine. People differ, so treat the numbers as a guide, not a cutoff.
Daily limits
For most healthy adults, up to about 400 mg a day is considered safe. If you are pregnant or trying to conceive, the American College of Obstetricians and Gynecologists suggests staying under 200 mg a day.
Caffeine can also worsen anxiety, panic, and palpitations in some people. Cutting back slowly avoids withdrawal headaches.
Take the Sleep Hygiene Score to see what else may be affecting your sleep.
Education only. This tool gives general information. It isn’t medical advice, a diagnosis, or a substitute for care from your own provider. Nothing you enter is sent anywhere or saved; it all stays in your browser.
If you are in crisis or thinking about hurting yourself, call or text 988 (Suicide & Crisis Lifeline, 24/7). If you are in immediate danger, call 911.
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Want to talk it through with a provider?
Keystone Psychiatry offers outpatient psychiatric care in Luzerne, PA.
Schedule an appointment Call 570-818-2853