Budgeting with a Repayment Mortgage

[Steve Fosdick]

I have set up a mortgage loan according to the tutorial, i.e. with a
fixed asset to represent the house, a liability account to represent
the loan and an expense account for the interest.

This is for a repayment mortgage, i.e. one where the sum paid to the
mortgage lender is the same each period, in my case a calendar month,
but the proportions of interest and capital repayment change over time
with the interest becoming a smaller proportion and the capital
repayment a larger proportion.

I am now trying to set up a budget but this does not seem to make
things particularly simple.  The intention of the budget is to manage
the combined balance of my current accounts and credit cards.  As my
income is approximately the same from one month to the next my first
idea was to use an expense budget and set the figures so that the total
is less than or equal to my average monthly income but this mortgage
repayment does not make this easy as the larger part of it is outside
the expense account tree.

Is there a different type of budget I should be using here?  Any tips?