Caffeine Calculator

Caffeine half-life tracker.

Caffeine remaining (mg) 122.96

Step-by-step with your numbers:

1. Values used:

2. Caffeine consumed = 200 mg

3. Hours since consumed = 4

4. Caffeine remaining = 122.96mg

Did we solve your problem today?

Caffeine half-life is ~5.7 hours — how much is still in your system.

FAQ

Sleep impact?

Half your caffeine from lunch could still be active at bedtime.