Calculator for the halflife given the rate of decay per period
This function calculates the time or periods required to reduce to half of its initial value for a given decrease per period.
Alternatively, the decrease can be calculated in % per period, which is required to halve the initial value in the specified time or periods.

\(\displaystyle t = \frac{log(0.5)}{log(1\frac{d}{100})}\)
\(\displaystyle d=(e^{\left(\frac{log(0.5)}{t}\right)}1)\cdot 100\)
