To purchase a $300K house, you may need to make between $50,000 and $74,500 a year. This is a rule of thumb, and the  specific salary will vary depending on your credit score, debt-to-income ratio, the type of home loan, loan term, and mortgage rate. Still, with a 3.5% down payment on a 30-year fixed-rate loan at 4.5 percent, you should be able to afford a $300,000 house with an annual salary of $74,500.