Returns the interest rate per period of a loan or an investment. For example, use 6%/4 for quarterly payments at 6% APR.
| Name | Type | Description |
| arg1 | number | Is the total number of payment periods for the loan or investment. |
| arg2 | number | Is the payment made each period and cannot change over the life of the loan or investment. |
| arg3 | number | Is the present value: the total amount that a series of future payments is worth now. |
| arg4 | number | Is the future value, or a cash balance you want to attain after the last payment is made. If omitted, uses Fv = 0. |
| arg5 | number | Is a logical value: payment at the beginning of the period = 1; payment at the end of the period = 0 or omitted. |
| arg6 | number | Is your guess for what the rate will be; if omitted, Guess = 0.1 (10 percent). |