Free Tool · SleepMetric
Your Exact Caffeine Cutoff
Time — Calculated
Enter your wake time, bedtime, and sensitivity. We’ll calculate your precise cutoff using caffeine’s half-life science and show you exactly how much is still active in your system at bedtime.
The half-life science: Caffeine has a biological half-life of 5–6 hours. A 200mg coffee at 3PM still leaves 100mg active at 9PM and 50mg at 2AM — directly blocking adenosine receptors and delaying sleep onset. This calculator finds your exact safe cutoff based on your inputs.
Step 1 · Your Schedule
Target wake-up time
The time you need to be alert — not just awake
Target bedtime
When you plan to fall asleep
Caffeine sensitivity
How strongly does caffeine affect your sleep?
Step 2 · Your Caffeine Source
What do you drink?
Select your primary caffeine source
How many servings per session?
2
Last caffeine by
—
—Total Caffeine
—Cutoff Time
—Active at Bedtime
Your Caffeine Day Timeline
Caffeine Remaining In Your System
Science-Backed Caffeine Strategies
Want the full sleep optimization system?
The Deep Sleep Protocol covers caffeine timing, light exposure, temperature, and a complete recovery framework — built around your chronotype and schedule.