A mortgage payment would count on your budget as a:

• fixed expense
  A mortgage payment is a fixed expense because you can predict you'll pay it on a consistent basis. Other fixed expenses include other loan payments, tuition, rent and fixed utilities that don't vary from month to month.
• unfixed expense
  A mortgage payment is a fixed expense because you can predict you'll pay it on a consistent basis. Other fixed expenses include other loan payments, tuition, rent and fixed utilities that don't vary from month to month.
• discretionary expense
  A mortgage payment is a fixed expense because you can predict you'll pay it on a consistent basis. Other fixed expenses include other loan payments, tuition, rent and fixed utilities that don't vary from month to month.