FORMULABANK

When one wants to find the interest rate or how large the growth per period has been, and the initial value, the final value, and the number of periods are known.

$r=\sqrt[n]{\frac{k_n}{k_0}}-1$

K_n = The final capital/the final value
K₀ = The initial capital/the initial value
r = The interest rate/growth rate in % per period
n = Number of periods