How this calculator works
One discount period must match the interest rate: monthly rates need months, while annual rates need years. The model has one payment at the end and no interim cash flows. A zero rate makes present and future values equal but cannot reveal a unique term. Negative rates are allowed above -100%.
Formula
PV = FV/(1 + i)^n. FV = PV(1 + i)^n. i = (FV/PV)^(1/n) - 1. n = ln(FV/PV)/ln(1 + i).
Worked example
Discounting $1,210 for two periods at 10% gives $1,000 today. At 0%, $500 payable after eight periods is worth $500.
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Frequently asked questions
Is the rate annual?
Only when a period means one year. Keep the period and rate on the same basis.
Does present value include an annuity?
This page discounts one amount. Use PVIFA for equal payments over several periods.
What does negative interest mean?
A future dollar can be worth more than a current dollar under a negative discount rate.