mg
hr
hr
0 mg
Estimated caffeine remaining
How This Calculator Works
The calculator uses an exponential half-life model: remaining caffeine equals dose multiplied by 0.5 raised to elapsed hours divided by selected half-life. It is useful for planning because caffeine does not disappear all at once.
| Search intent | Answer on this page |
|---|---|
| caffeine half life calculator | Estimate remaining caffeine from dose, time, and half-life. |
| how much caffeine is left after 6 hours | Use dose and 6 hours elapsed to see a transparent estimate. |
| caffeine before bed calculator | Add hours until bedtime to estimate remaining caffeine at bedtime. |
Limits
Actual caffeine clearance varies with genetics, pregnancy, medications, liver function, nicotine use, and individual sensitivity. This page is educational and does not diagnose insomnia or caffeine sensitivity.