Caffeine Cutoff Calculator
Find the best time to stop caffeine so you can fall asleep easier. This tool estimates caffeine clearance using an average half-life and your sensitivity setting. It’s a practical guideline, not medical advice.
Calculator
Assumes caffeine half-life ≈ 5 hours (varies widely). Choose sensitivity to reflect how long you feel caffeine effects.
Stop caffeine by
⚠️ This time is on the previous day.
ℹ️ This tool provides general guidance, not medical advice. Caffeine tolerance varies widely between individuals. If you are pregnant, breastfeeding, or have heart/kidney conditions, consult a medical professional.
FAQ
Why does caffeine affect sleep?
Caffeine blocks adenosine, a chemical that helps you feel sleepy. Even moderate amounts late in the day can reduce sleep quality.
What is caffeine half-life?
Half-life is the time it takes for caffeine levels to drop by ~50%. Many adults average around 5 hours, but it can vary from ~2 to 10+ hours.
Why do people respond differently?
Genetics, liver enzymes, medications, sleep debt, and hormonal factors can all affect caffeine metabolism and sensitivity.
How much caffeine is “safe”?
Many guidelines suggest up to ~400 mg/day for healthy adults, but some people are much more sensitive. If sleep is a priority, reduce intake earlier in the day.
How this caffeine cutoff calculator works
The calculator estimates when your last caffeine intake should happen before bedtime. It uses your selected bedtime, caffeine amount, caffeine half-life, sensitivity, and target remaining caffeine level at bedtime.
Caffeine formula used
Remaining caffeine = initial caffeine × 0.5^(hours elapsed / half-life). Because caffeine response varies, treat the result as a practical planning estimate, not medical advice.
Practical caffeine cutoff tips
Use the cutoff as a conservative planning point, not a strict medical rule. If you are sensitive to caffeine, anxious, pregnant, using stimulant medication, or sleeping poorly, choose a longer buffer and a lower target level.
Caffeine is not only in coffee. Tea, energy drinks, cola, pre-workout products, chocolate, and some pain relievers may also contain caffeine. For better sleep, track your last meaningful caffeine dose for a week and compare it with your sleep quality.