Finance Calculator
A time value of money solver. Fill in any four of the five variables — periods, rate, present value, payment, and future value — and choose which one to solve for.
Inputs
How to use this calculator
1. Choose what to solve for
Pick one of FV, PV, PMT, N, or I/Y. That field disappears from the form because the calculator works it out from the other four.
2. Mind the signs
Money you pay out is entered as a negative number and money you receive is positive. A typical investment has a negative PV and PMT and a positive FV.
3. Match the period to the rate
N counts periods and I/Y is the rate per period. For monthly cash flows, use months for N and the monthly rate for I/Y (annual rate divided by 12).
4. Set the payment timing
Use End of period for ordinary annuities (the default) or Beginning for annuities due, where each payment lands one period earlier and so earns a little more interest.
About the time value of money
What is the time value of money?
It is the idea that a dollar today is worth more than a dollar in the future, because money on hand can be invested to earn a return. The TVM equation ties together present value, future value, periodic payments, the number of periods, and the interest rate so that any one can be found from the others.
Why are some values negative?
This calculator follows the cash-flow sign convention: money you pay out is negative and money you receive is positive. For example, an investment you fund is a negative present value, while the balance you withdraw later is a positive future value.
The underlying equation
PV × (1 + i)N + PMT × (1 + i × type) × ((1 + i)N − 1) / i + FV = 0, where i = I/Y ÷ 100 and type is 0 for end-of-period or 1 for beginning. The rate is found by a numerical search; the others have closed-form solutions.