Start with your monthly take-home pay and work backwards

The most useful number is not what a lender will approve you for—it's what you can actually pay each month without breaking the rest of your budget. Most lenders use a debt-to-income ratio, which means they will lend you money if your total monthly debt payments (mortgage, car loans, credit cards, student loans) don't exceed 43% of your gross monthly income. But that ratio doesn't account for groceries, utilities, insurance, childcare, or anything else you actually need to live.

Start instead with your monthly take-home pay—the amount that actually hits your bank account after taxes. Subtract what you spend on everything except housing: food, transportation, insurance, childcare, debt payments, utilities, phone, internet, and a small buffer for unexpected costs. What's left is the maximum you should spend on housing. If you take home $4,000 a month and spend $1,500 on non-housing expenses, you have $2,500 available. That $2,500 needs to cover your mortgage payment, property taxes, homeowners insurance, and mortgage insurance if you put down less than 20%.

Key Takeaways

  • Your maximum house payment should be what's left after you subtract all non-housing expenses from your monthly take-home pay, not what a lender will approve.
  • The monthly payment includes the mortgage itself plus property taxes, homeowners insurance, and mortgage insurance—not just the loan amount.
  • A mortgage calculator that shows you the full monthly cost (often called PITI: principal, interest, taxes, insurance) is more useful than a pre-approval letter.
  • Putting down 20% or more eliminates mortgage insurance and lowers your monthly payment significantly, which changes how much house you can afford.
  • Your debt-to-income ratio matters to lenders, but your actual monthly budget matters more to your financial stability.

Use a mortgage calculator that includes taxes and insurance

A basic mortgage calculator that only shows principal and interest will mislead you. Property taxes and homeowners insurance can add 30% to 50% to your monthly payment depending on where you live, and mortgage insurance adds another 0.5% to 1.5% of the loan amount each year if you put down less than 20%.

Use a calculator that shows PITI (principal, interest, taxes, insurance). You'll need to know or estimate your local property tax rate—your county assessor's website has this, or a real estate agent can tell you. For insurance, call a homeowners insurance company and ask for a quote on a house in your price range in your area. Plug those real numbers in. If you're putting down less than 20%, the calculator should automatically add mortgage insurance. The total monthly payment it shows you is what you actually need to budget for.

Account for the down payment you actually have

The down payment changes everything. If you have $60,000 saved and you're looking at a $300,000 house, that's 20% down. Your mortgage insurance disappears, and your monthly payment drops. If you only have $30,000 saved, that's 10% down, and you'll pay mortgage insurance for years until you reach 20% equity—or until you refinance.

Work backwards from your down payment. If you have $40,000 saved and you want to put down 20%, the maximum house price is $200,000. If you want to buy a $250,000 house with that $40,000, you're putting down 16%, which means mortgage insurance. Calculate both scenarios in your mortgage calculator and see which monthly payment fits your budget. Don't stretch to a higher price just because a lender will approve it.

Check your debt-to-income ratio against what lenders actually require

Lenders have their own rules, and you need to know whether you'll actually be approved before you start house hunting. Most conventional lenders want your total monthly debt payments to be no more than 43% of your gross monthly income (the amount before taxes). Some will go to 50% if you have excellent credit and a large down payment, but 43% is the standard.

To calculate this: add up all your monthly debt payments—mortgage payment (estimated from your calculator), car loans, student loans, credit cards, personal loans, anything with a monthly bill. Divide that total by your gross monthly income. If the result is 43% or less, you're in the range most lenders will consider. If it's higher, you either need to pay down other debts first, increase your income, or lower your target house price. This is separate from your personal budget calculation—it's just the lender's threshold.

Factor in closing costs and moving expenses

Closing costs typically run 2% to 5% of the purchase price and include the lender's origination fee, appraisal, title search, title insurance, and attorney fees. On a $300,000 house, that's $6,000 to $15,000. You can sometimes roll these into your loan, but that increases your monthly payment. It's better to have the cash on hand.

You'll also need money for inspections, repairs the inspection uncovers, moving, and immediate home repairs or updates. If you're stretching to afford the house itself, you won't have cushion for these costs. Add at least 5% to 10% of the purchase price to your total savings requirement before you start looking.

Get pre-approved to see what lenders will actually lend

A pre-approval letter from a lender shows you the maximum loan amount they'll give you based on your credit, income, and debts. It's not a promise—the lender will re-verify everything before closing—but it's a real number based on your actual financial situation. You can get pre-approved from multiple lenders in a few days, and it doesn't hurt your credit score (multiple mortgage inquiries within 14 days count as one inquiry).

Compare the pre-approval amount against your personal budget calculation. If the lender will approve you for $350,000 but your budget says you can afford $280,000, use your budget number. The lender is not responsible for your grocery bills or car repairs. You are.

Adjust your target price if the numbers don't work

If your budget and the lender's pre-approval don't align, you have three levers: increase your down payment, pay down other debts, or lower your target price. Increasing your down payment reduces the loan amount and eliminates or reduces mortgage insurance. Paying down credit cards or car loans lowers your monthly debt obligations and improves your debt-to-income ratio. Lowering your target price is the most direct option if the other two aren't realistic in your timeline.

Some people buy a less expensive house now and upgrade later. Others wait a year or two to save more for a down payment or to pay off student loans. There's no shame in either choice. Buying more house than you can comfortably afford is how people end up house-poor—paying so much for the mortgage that they can't afford maintenance, property taxes, or anything else.

Frequently Asked Questions

What if I have a co-borrower or spouse with separate income?

Both incomes count toward your debt-to-income ratio and your pre-approval amount. However, both of your debts also count. If one of you has significant student loans or credit card debt, it reduces how much you can borrow together. Some couples find it's better to apply with only one income if the other person has high debt, but that also means lower approval amounts.

Does my credit score affect how much I can borrow?

Yes. A higher credit score gets you a lower interest rate, which lowers your monthly payment and means you can afford a higher price. A lower score increases your rate and monthly payment. The difference between a 740 score and a 620 score can be 1% to 2% in interest rate, which translates to $100 to $200 more per month on a $300,000 loan. Improving your credit score before you apply can increase your buying power.

Should I use my entire savings as a down payment?

No. You need to keep an emergency fund separate from your down payment. Most financial advisors recommend keeping three to six months of expenses in savings before you buy. If you use all your savings for the down payment, you'll have no buffer for a job loss, medical emergency, or major home repair in your first year of ownership.

Can I afford a house if I'm self-employed?

Yes, but lenders require more documentation. They typically want two years of tax returns and may average your income over that period if it's variable. Some lenders also require a business license and bank statements. Self-employed borrowers often need a larger down payment (15% to 20%) to offset the perceived risk. Start the pre-approval process early so you know what documents you'll need.

What if I get approved for more than I think I can afford?

Use your personal budget number, not the lender's approval. The lender is evaluating risk to themselves, not your quality of life. If your budget says $280,000 and they approve you for $380,000, the approval doesn't change your actual monthly expenses. Stick with what you can afford without stress.