Module nper 

Number of periods with payments (NPER). How many periods for an annuity cashflow to grow from a present value to a future value at a periodic rate?

Excel / Google Sheets equivalent: NPER.

Error handling (v0.1+)

All entry points return FinanceResult. Invalid rates, non-negative payments (Excel sign convention), or unsolvable combinations yield FinanceError — they do not panic.

Structs

NperSolution

Solution struct for an NPER calculation.

Functions

nper

Returns the number of periods for an annuity (payments) to reach a future value.

nper_due

Number of periods when payments are due at the beginning of each period (Excel type=1).

nper_due_solution

nper_due with a solution struct.

nper_solution

nper with a solution struct (formula string + inputs).