Nutrition
Time to reach a target level
Rearranges the decay curve to find when a threshold is crossed.
The Formula
hours = half life x log(target / dose) / log(0.5)
Rearranges the decay curve to find when a threshold is crossed.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| hours | Time to target | hours | Hours until the level falls to the target. |
| target | Target level | mg | The level you want to fall below, in milligrams. |
| dose | Dose | mg | The original amount, in milligrams. |
What Each Symbol Means
hourshours
Time to target
Hours until the level falls to the target.
targetmg
Target level
The level you want to fall below, in milligrams.
dosemg
Dose
The original amount, in milligrams.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate caffeine half life page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate Caffeine Half Life, filed under Health. Every number the guide produces comes from substituting into this one line.