Tools · SleepCaffeine & Sleep
Caffeine & Sleep
Cutoff Calculator
Caffeine has a half-life of about five hours — half of your afternoon coffee can still be circulating at midnight. See what's left at bedtime and when your last cup should be.
Your intake
mg
Brewed coffee ≈ 95 mg/cup · espresso ≈ 63 mg/shot · energy drink ≈ 80–150 mg.Average adult ≈ 5 h. Higher = more sensitive.
Caffeine remaining at bedtime
— mg
Latest cutoff for < 50 mg by bedtime—
Time to clear to 25 mg—
Decay from now to bedtime
This calculator is for educational purposes only and is not medical advice, diagnosis, or treatment. Results are estimates based on published formulas and population averages — your individual values may differ. Nothing here is calculated on a server: everything runs in your browser and no data is stored or sent anywhere. Always consult a qualified clinician before making health, medication, or training decisions.