Caffeine Level Calculator & Tracker
Estimate your active caffeine level over the day. Log drinks, adjust caffeine half-life and body weight, and see when your curve drops toward sleep-safe levels.
Free caffeine level calculator
Use the web tracker to estimate how much caffeine is still active after coffee, tea, energy drinks, or custom caffeine amounts. The graph shows a Garmin-style caffeine curve for the current day.
How the estimate works
The calculator applies caffeine half-life decay over time and adjusts the estimate using your body weight. For more detail, read how Caffeine Tracker works.
Use it before installing on Garmin
Try different drinks, intake times, half-life presets, and sleep-safe thresholds before using the same model in the Garmin Connect IQ widget.
Private browser storage
Drinks and settings are stored locally in this browser. The tracker is an estimate for personal planning only and is not medical advice.
Caffeine tracker FAQ
Is this caffeine tracker a blood test?
No. It is a model-based estimate from the drinks you log, your body weight, and your selected caffeine half-life.
Does the web tracker store my data on a server?
No. Drinks and settings are stored locally in your browser.
How do I choose a caffeine half-life?
Use the caffeine half-life wizard to estimate a practical preset, then apply that value in the web tracker or Garmin widget.