IPMT function
This article describes the formula syntax and usage of the IPMTfunction in Microsoft Excel.
Description
Returns the interest payment for a given period for an investment based on periodic, constant payments and a constant interest rate.
Syntax
IPMT(rate, per, nper, pv, [fv], [type])
The IPMT function syntax has the following arguments:

Rate Required. The interest rate per period.

Per Required. The period for which you want to find the interest and must be in the range 1 to nper.

Nper Required. The total number of payment periods in an annuity.

Pv Required. The present value, or the lumpsum amount that a series of future payments is worth right now.

Fv Optional. The future value, or a cash balance you want to attain after the last payment is made. If fv is omitted, it is assumed to be 0 (the future value of a loan, for example, is 0).

Type Optional. The number 0 or 1 and indicates when payments are due. If type is omitted, it is assumed to be 0.
Set type equal to 
If payments are due 
0 
At the end of the period 
1 
At the beginning of the period 
Remarks

Make sure that you are consistent about the units you use for specifying rate and nper. If you make monthly payments on a fouryear loan at 12 percent annual interest, use 12%/12 for rate and 4*12 for nper. If you make annual payments on the same loan, use 12% for rate and 4 for nper.

For all the arguments, cash you pay out, such as deposits to savings, is represented by negative numbers; cash you receive, such as dividend checks, is represented by positive numbers.
Example
The example may be easier to understand if you copy it to a blank worksheet.
How do I copy an example?

Select the example in this article. If you are copying the example in Excel Web App, copy and paste one cell at a time.
Important Do not select the row or column headers.
Selecting an example from Help

Press CTRL+C.

Create a blank workbook or worksheet.

In the worksheet, select cell A1, and press CTRL+V. If you are working in Excel Web App, repeat copying and pasting for each cell in the example.
Important For the example to work properly, you must paste it into cell A1 of the worksheet.

To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Formulas tab, in the Formula Auditing group, click the Show Formulas button.
After you copy the example to a blank worksheet, you can adapt it to suit your needs.
Note The interest rate is divided by 12 to get a monthly rate. The years the money is paid out is multiplied by 12 to get the number of payments.