Start with your monthly take-home pay

The most straightforward way to figure out what house payment fits your budget is to look at what you actually bring home each month after taxes. Most lenders use a rule called the debt-to-income ratio, which compares your total monthly debt payments to your gross monthly income (before taxes). But for your own planning, working backward from what you keep is more honest.

Take your monthly paycheck — the amount that actually lands in your account. Add any other income you receive regularly: a spouse's salary, child support, pension payments, or side work you do consistently. This is the number you work from, not your gross salary.

From that total, subtract what you already owe each month: car loans, student loans, credit card minimums, child support, alimony, and any other debts with a fixed payment. What's left is the pool of money available for housing, food, utilities, insurance, gas, and everything else. Your house payment needs to fit inside that pool, not consume it.

Key Takeaways

  • Most lenders will approve you for a house payment up to 28 percent of your gross monthly income, but that does not mean you should spend that much.
  • Your actual affordability depends on your take-home pay after taxes, minus the debts you already owe, minus the cost of property taxes, insurance, and maintenance in your area.
  • A mortgage payment is only one part of homeownership — property taxes, homeowners insurance, and repairs can equal or exceed the loan payment itself.
  • The down payment you can afford affects both the loan amount and your monthly payment, so saving more upfront lowers what you need to borrow.
  • Lenders look at your credit score, debt history, and income stability, and a lower score or recent missed payments will shrink the amount they will lend you.

Account for taxes, insurance, and maintenance

The mortgage payment itself — principal and interest — is only part of what homeownership costs each month. You also pay property taxes, homeowners insurance, and eventually maintenance and repairs. In many parts of the country, these costs together equal or exceed the loan payment.

Property taxes vary dramatically by location. Some states and counties charge less than 0.5 percent of the home's value per year; others charge over 2 percent. A $300,000 house in a high-tax area can cost $500 to $600 per month in property taxes alone. Homeowners insurance typically runs $100 to $200 per month depending on the home's age, location, and your coverage level. If you put down less than 20 percent, you will also pay mortgage insurance (PMI), which can add $100 to $300 per month.

For maintenance and repairs, financial advisors often suggest setting aside 1 percent of the home's purchase price per year. On a $300,000 house, that is $3,000 per year, or $250 per month. A new roof, a failing water heater, or foundation work can cost thousands in a single year, so this is not optional — it is a realistic cost of owning a home.

Add all of these together: mortgage payment + property tax + insurance + PMI (if applicable) + maintenance reserve. That total is what homeownership actually costs you each month. It should not exceed 30 to 35 percent of your take-home pay, and ideally should be closer to 25 percent.

Use the debt-to-income ratio lenders check

When you explore for a mortgage, lenders calculate your front-end ratio and back-end ratio. The front-end ratio is your total housing costs (mortgage, taxes, insurance, PMI) divided by your gross monthly income. Most lenders will approve you if this is 28 percent or lower, though some will go to 31 percent.

The back-end ratio includes all your debts — housing plus car loans, student loans, credit cards, and anything else with a monthly payment — divided by gross income. Most lenders cap this at 43 percent, though some will go to 50 percent if your credit is strong.

Here is a concrete example: if you earn $5,000 gross per month and have $400 in existing debt payments, your back-end ratio is already 8 percent. A lender might approve you for a housing payment of up to $1,400 (28 percent of $5,000), but your total debt would then be $1,800, which is 36 percent of gross income. That fits within the 43 percent cap, so the lender would approve it — but it leaves you very little room for anything else.

How your down payment changes what you can afford

The more money you put down, the smaller the loan you need to borrow, and the smaller your monthly payment. A larger down payment also means you avoid mortgage insurance, which saves you $100 to $300 per month.

If you have $60,000 saved and are looking at a $300,000 house, putting down 20 percent ($60,000) means you borrow $240,000. Putting down 10 percent ($30,000) means you borrow $270,000 and pay PMI on top of the higher loan. The difference in monthly payment between these two scenarios is roughly $200 to $250, depending on interest rates.

If you are uncertain how much house you can afford, one practical approach is to decide how much you can save for a down payment first. Then use a mortgage calculator to see what loan amount that down payment supports at your local interest rate. That loan amount, divided by the price of homes in your area, tells you the price range you can realistically pursue.

What lenders look at beyond income

Your income is only one part of the lending decision. Lenders also examine your credit score, your payment history, how long you have been at your current job, and whether you have recent missed payments or collections accounts.

A credit score below 620 makes it very difficult to get approved for a conventional mortgage at all. Scores between 620 and 680 typically may have access to you for a loan, but at a higher interest rate, which increases your monthly payment. Scores above 740 usually get the best rates available.

If you have changed jobs recently, been self-employed for less than two years, or have a gap in employment, lenders may require more documentation or may approve you for a smaller loan than your income alone would suggest. A recent missed payment, even if you caught up, signals risk to a lender and can raise your interest rate or lower your approval amount.

The difference between what you can afford and what you should borrow

A lender's approval is not a recommendation — it is a maximum. Just because a lender will approve you for a $400,000 mortgage does not mean you should take it. Lenders are willing to lend you money at the edge of what you can technically pay; they are not concerned with whether you have money left over for emergencies, retirement savings, or a vacation.

A practical rule is to aim for a house payment (including taxes, insurance, and PMI) that is no more than 25 percent of your take-home pay. This leaves room for other financial goals and for the unexpected costs that come with homeownership. If a lender approves you for more, that approval reflects their risk tolerance, not your actual comfort zone.

Before you start house hunting, sit down with a calculator and your last few paychecks. Know your actual take-home number, subtract your existing debts, and see what is left. That honest number is more useful than any lender's approval letter.

Frequently Asked Questions

What if my income varies month to month?

Lenders typically average your income over the past two years if you are self-employed or work on commission. If your income has been rising, they may use a lower average to be conservative. Document your income with tax returns and recent pay stubs, and be prepared to explain any dips or gaps.

Does my spouse's income count if we are not married?

No. Only income in your name counts toward your approval. If you are married or in a registered domestic partnership, your spouse's income can be included, but so can their debts. Both of you will be on the mortgage and responsible for the loan.

Can I get approved for a bigger loan if I have a co-signer?

Yes. A co-signer's income and credit are added to the process, which can increase your approval amount. However, the co-signer is legally responsible for the loan if you do not pay, and it counts as their debt for their own future borrowing.

What happens to my affordability if interest rates go up?

A higher interest rate increases your monthly payment on the same loan amount. For every 1 percent increase in the interest rate, your monthly payment rises roughly 10 percent. If rates rise between the time you are pre-approved and the time you close, your actual payment will be higher than you expected.

Should I use an online calculator or talk to a lender?

Start with an online calculator to get a rough idea of what you might afford. Then talk to a lender or mortgage broker to get pre-approved, which shows you a real approval amount based on your actual credit, income, and debts. Pre-approval is free and does not obligate you to borrow.