This calculator calculates the number of periods of annuity using present value of annuity($) , rate(%), payment / cash flows values.
Formula:
NPVA = ln (1-((PV x r) / P))^-1 / ln(1 + r)
NPVA = Number of Periods of Annuity
FV = Future Value of Annuity
r = Rate
P = Payment / Cash Flows