Interest Rate Calculator
Find the interest rate needed to reach a savings goal or reverse-calculate loan rates.
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Frequently Asked Questions
How do I calculate the interest rate needed to reach a goal?
Use the compound interest formula rearranged for rate: r = (FV/PV)^(1/n) - 1, where FV is future value, PV is present value and n is years. For example, to grow $10,000 to $20,000 in 10 years requires a 7.18% annual rate.
What is the Rule of 72?
The Rule of 72 estimates how long it takes to double money: divide 72 by the annual interest rate. At 6%, money doubles in 12 years. At 8%, in 9 years. At 12%, in 6 years. It also works in reverse: to double money in 8 years, you need a 9% rate.
What interest rate does the stock market return?
The S&P 500 has historically returned about 10% annually before inflation, or approximately 7% after inflation. However returns vary enormously year to year. Individual stocks, real estate and other assets have different expected return rates and risk levels.