House Affordability Calculator

Last updated July 2, 2026

Lenders use a set of standardized ratios to determine how much mortgage a borrower qualifies for, but those ratios define the maximum — not what's financially comfortable. The conventional rule is that total housing costs (mortgage principal, interest, taxes, insurance, and HOA if applicable) should not exceed 28 percent of gross monthly income, and total debt payments should not exceed 36 percent. These thresholds are often called the "28/36 rule." On a $90,000 annual gross income — $7,500 per month — those ratios allow a maximum housing payment of $2,100 and total debt of $2,700. A household already carrying $500 in student loan and car payments has $2,200 available for total debt, leaving only $2,200 for housing.

Many lenders have loosened these thresholds in practice, qualifying borrowers at debt-to-income ratios of 43 to 50 percent for FHA and conventional loans. Qualifying for a loan and affording a loan are not the same thing. A family stretched to 43 percent DTI has very little financial margin for maintenance expenses, childcare cost increases, or income reduction. The meaningful affordability question isn't "how much will the bank lend me?" — it's "how much can I spend on housing and still comfortably fund retirement savings, maintain an emergency fund, and handle the costs that come with owning the home?" Financial planners frequently recommend targeting housing costs at 25 percent or less of take-home pay, not gross income.

The calculation shows affordability based on your take-home pay and total cash obligations, not just the bank's qualifying ratios. The difference between the maximum the lender will approve and what leaves you financially stable can be $100,000 or more in loan amount. Know the number that works for your actual financial life, not just the one that clears underwriting.