NPER

FINANCE.NPER(rate, payment_amount, value, future_value = 0, end_or_start = 0)

Calculates the number of payment periods for an investment based on constant-amount periodic payments and a constant interest rate.

rate: The interest rate.
periodic_amount: Amount of each payment to be made.
value: Current value of the annuity.
future_value: Future value remaining after the final payment has been made.
end_or_beginning: Whether payments are due at the end (0) or the beginning (1) of each period.