The formula for the future value of an ordinary annuity is F = P * ( [1 + I]^N - 1 )/I, where P is the payment amount. I is equal to the interest (discount) rate.

The present value interest factor (PVIF) formula is used to calculate the current worth of a lump sum to be received at a future date. The present value interest factor of annuity (PVIFA) is used ...