how to calculate interest and principal on part and part mortgage 30 April 2012 at 2:46PM in House Buying, Renting & Selling 4 replies 553 views

mysti77

Hiya,

I know you can get loan amortiation spreadsheets in excel but these only allow you to work out if you were doing full repayment.

If I were paying interet only on a portion of my mortgage and repayment on the rest, how do I work out how much of my monthly payment is interest and how much is repayment?

Thanks

jjlandlord

You use the spreadsheet on the part that is repayment, this gives you how much is interest and how much is capital on that part.
The other part is obviously interests only.

mysti77

but I don't repay on the full amount. e.g. my total loan amt is 160,000 but I only do repayment on 15,000 and the rest is interest only.

jjlandlord

Yes, that's why I suggested that you can use the standard Excel sheet you mentioned on the £15k, which will give you the monthly capital repayments and interest on this amount.
Considering that the rest is interest only you have your answer so as to how much of the total monthly payments are capital repayments.

DVardysShadow

mysti77 wrote: »

but I don't repay on the full amount. e.g. my total loan amt is 160,000 but I only do repayment on 15,000 and the rest is interest only.

Then do what he said:

jjlandlord wrote: »

You use the spreadsheet on the part that is repayment [£15000], this gives you how much is interest and how much is capital on that part.
The other part is obviously interests only [£145000].

You didn't really need me to do that did you?