Calculators

Financial

Interest & APR

Calculator Use

Create a printable interest rate table to lookup the interest rate required to grow $1 to a future value amount.

Starting with the formula for future value

and solving the equation for interest rate (i), we use the formula

replacing the present value sum with $1, PV = $1

let I = i * 100 then the rate in percentage form is given by

where FV is the future value, PV is the investment principal amount = $1, i is the interest rate in decimal form and n is the period number. PV is the amount of money = $1 to be invested at the end of each equal period which will grow to FV after n Number of Time Periods and at an Interest Rate i per period.  i is in decimal form for calculations.

If you decide to drop the $1 your final formula is

You can, for example, look up I in the table to find an applicable interest rate for your desired investment performance.

Example Use: You want to invest $10,000 and triple your investment over time.  How many years will it take for you to triple your investment and at what interest rate?

1. Create a table that includes FV = $3.00 since the table is based on $1.00 investments. Also include a sufficient range of rows for n.
   1. Start 5 colums of FV at 2 with increments of 0.5
   2. Start 20 rows of n at 10 with increments of 1
2. Look at the FV column for $3.00.
3. In the $3.00 column you can lookup interest rates and the corresponding number of periods, n, it will take to triple your investment.