How much caffeine will be left at bedtime?
What have you had today?
Pick what you drank and we'll tell you how much caffeine will still be in you at bedtime, and the latest time one more still fits.
Coffee
Which one?
Size
When
How long it took to drink
Can I still have...?
Your caffeine today
Drag a drink to see how timing changes your night.
Chart values as text
Today's drinks
Nothing added yet.
This week
Make it more accurate (30 seconds)
Many guidelines suggest staying under 200 mg a day during pregnancy. Follow the advice of your own clinician.
Liver conditions and some medications change how fast caffeine clears. If that applies to you, these numbers will be off; ask a clinician.
What the research says
- In a sleep-lab trial, 400 mg of caffeine taken 6 hours before bed cut sleep by more than an hour, and people often did not notice. Drake et al., 2013
- A 2023 meta-analysis found caffeine cut total sleep by about 45 minutes, and suggested stopping about 8.8 hours before bed for a cup of coffee and 13.2 hours for a pre-workout dose. Gardiner et al., 2023
- The FDA cites 400 mg a day as an amount not generally associated with negative effects for most healthy adults. FDA
These are group averages. CaffeineIQ does not estimate how much sleep you personally lose.
Drinks and foods
Loading drinks and foods, each with its published caffeine and a link to its source. "Approx." marks estimates.
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Sources
Values come from brand pages, USDA FoodData Central, DailyMed (medicine labels), Open Food Facts, and the CSPI caffeine chart. Every row links to its source. Open Food Facts data is available under the Open Database License; those rows are crowd-entered and tagged approx.
How it works
- 01 In
Caffeine from each drink reaches your blood within about an hour, spread across however long it took you to drink it.
- 02 Out
Your body then clears it gradually: for a typical adult, half is gone after about 5 hours. Your answers under "Make it more accurate" adjust that. Every drink adds up into one curve.
- 03 Bedtime
The curve is compared with your sleep-friendly level at bedtime and through the night. That gives the number at bedtime, when you are back under it, and the latest time each drink still fits.
It is an estimate from averages, not a measurement. For what caffeine does to sleep, see What the research says.
CaffeineIQ for iPhone
The iPhone app is coming soon. Everything on this page keeps working without it.
- Your bedtime number on the lock screen. A widget shows the caffeine left at bedtime and your cutoff.
- See what caffeine does to your sleep. It compares your nights using Apple Health, on your phone.
- A nudge before your cutoff. A reminder before the latest time your usual drink still fits.
About
CaffeineIQ is made by C6 Labs. The web tool is free and runs entirely in your browser.
Chart style inspired by caffeine-day by Charles Postiaux (MIT).