3) How much is the salary you need to make to afford a house worth $400,000?

Decide the monthly mortgage for 30 year loan, assuming the monthly rate = 5% / 12.

Calculate annual mortgage payment = monthly mortgage payment * 12.

How much percentage income would you be comfortable to use for a mortgage payment.

Annual mortgage payment / % of income for mortgage = annual income.

You can start with the mortgage example in our discussion of the time value of money and also include other considerations.