Solve any one variable of a time-value-of-money problem. Enter the four values you know — number of periods, interest rate, present value, payment, or future value — pick the tab for the unknown, and the calculator solves it, just like a five-key financial calculator. Each result comes with the sum of payments, total interest, and a period-by-period schedule.
Formula
All five tabs rearrange one identity. For a per-period rate i (= I/Y ÷ 100 ÷ P/Y),
N periods, and type = 1 for beginning-of-period payments (else 0):
PV × (1 + i)^N + PMT × (1 + i·type) × [ (1 + i)^N − 1 ] / i + FV = 0
FV, PV, and PMT have direct closed-form rearrangements; N comes from a logarithm; the rate I/Y is found by numerical search.
What each tab solves for
| Tab | You provide | It solves for |
|---|---|---|
| FV | N, I/Y, PV, PMT | the future value |
| PMT | N, I/Y, PV, FV | the periodic payment |
| I/Y | N, PV, PMT, FV | the annual rate |
| N | I/Y, PV, PMT, FV | the number of periods |
| PV | N, I/Y, PMT, FV | the present value |
Examples
$20,000 today, withdraw $2,000/year for 10 years at 6%
With PV = $20,000, PMT = −$2,000, N = 10, and I/Y = 6%, the future value is −$9,455.36. The payments sum to −$20,000 and the account earns $9,455.36 in interest over the ten periods.
Solving for the rate
Switch to the I/Y tab and enter PV = $20,000, PMT = −$2,000, N = 10, FV = −$9,455.36; the calculator searches for and returns a 6% annual rate.