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.

Your bedtime

Caffeine source

Caffeine sensitivity (how long you feel its effects)

Time between last caffeine and sleep

Half-life

Target caffeine at bedtime

Stop caffeine by

Stop caffeine by -

Caffeine remaining at bedtime -

Half-lives elapsed -

🕒 Tip: If you’re sensitive, stop even earlier and avoid caffeine “top-ups” in the afternoon.

How caffeine decreases over time

At cutoff time-

+ 2 hours-

+ 4 hours-

At bedtime-

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.