I assume your are using IPMT function or equivalent.

Have four columns for each period. The Present value of loan,Principle
payment, Interest, and Extra Payment.

A B C D
E
Value of Loan Interest Princilple Extra Payment Date
$500,000 =ipmt( ) A - B 0
column C-D =ipmt( ) A - B


"CAlloway" wrote:

I am confused. But I said "chart", and I actually have a spreadsheet. All I
want to be able to do is enter a date in a seperate column and then a dollar
amount in another. Then have Excel plug them into the existing data in date
order and re-calculate the balance. I'm relatively new to using Excel, but I
can't find anything on their help pages to cover this. Thanks.

"Joel" wrote:

I think you want to add another series to the chart. If you roght click on
the chart in the white area outside the plt and select source data. Then
click the series tab.

"CAlloway" wrote:

Hello,
I have created a chart for a loan I have. It shows the future payment dates
(bi-weekly), interest paid, principal paid and outstanding balance. It
calculates it out until the loan is repaid. What I would like to do is add 2
columns for additional payments. I want one column so I can input the date of
the extra payment, and the other the amount that is applied to the principal.
The trick is that I want Excel to take the date and insert it in
chronological order with the existing dates, and then take the amount off the
principal and re-calculate the rest of the data until the loan is paid down.
Oh, and not to calculate interest on that payment, since it's principal only.
Any help you can give would be great. Thanks!