Start with your debt-to-income ratio

Most lenders will not approve you for a mortgage if your monthly debt payments (car loans, student loans, credit cards, and the new mortgage payment) exceed 43 percent of your gross monthly income. Some lenders go up to 50 percent, but 43 is the standard threshold. This is the single number lenders check first.

To calculate yours: add up all your monthly debt payments, then divide by your gross monthly income before taxes. If you earn $5,000 per month and owe $1,500 in debt payments, your ratio is 30 percent. A mortgage payment of $1,200 would push you to 54 percent — over the limit at most lenders.

Your debt-to-income ratio matters more than your credit score or savings. A person with excellent credit and $50,000 saved can still be denied if their ratio is too high. Conversely, someone with a lower score but a strong ratio has a real path forward.

Key Takeaways

  • Lenders typically cap your total monthly debt payments at 43 percent of your gross income, though some allow up to 50 percent.
  • Your down payment size directly affects your monthly payment: 20 percent down means a lower payment and no mortgage insurance, while 3 percent down means a higher payment and added insurance costs.
  • Property taxes, homeowners insurance, and HOA fees (if applicable) are part of your housing cost and count toward your debt-to-income ratio.
  • You can reduce the mortgage payment you need by paying down existing debts before you apply, which lowers your ratio and increases the loan amount lenders will offer.

Calculate what your monthly payment will actually be

The mortgage payment itself is only part of your housing cost. Lenders use a figure called the housing ratio or front-end ratio, which caps your housing payment (mortgage principal, interest, property taxes, homeowners insurance, and mortgage insurance if applicable) at 28 percent of gross income. Some lenders go to 31 percent.

If you earn $5,000 per month, 28 percent is $1,400. That $1,400 must cover the mortgage payment, property taxes, insurance, and mortgage insurance all together. Property taxes and insurance vary by location and home price, so you cannot know the exact number until you have a specific property in mind. But you can estimate: property taxes typically run 0.5 to 2 percent of the home's value per year (divided by 12 for the monthly amount), and homeowners insurance usually costs $800 to $1,500 per year.

If you are buying a condo or townhome, add HOA fees to this calculation. They count as part of your housing payment for lending purposes.

Understand how down payment size changes affordability

A larger down payment lowers your monthly payment and removes the need for mortgage insurance (PMI). PMI is an extra monthly fee — typically 0.5 to 1.5 percent of the loan amount per year — that protects the lender if you default. It disappears once you reach 20 percent equity in the home, but until then it adds $100 to $300 per month to your payment depending on the loan size.

A 3 percent down payment on a $300,000 home means you borrow $291,000 and pay PMI. A 20 percent down payment means you borrow $240,000 and skip PMI entirely. The monthly payment difference is substantial — roughly $200 to $400 per month depending on interest rates.

If your debt-to-income ratio is tight, a larger down payment can be the difference between approval and denial. Paying down other debts first has the same effect: it lowers your ratio and frees up room in your housing budget.

Account for closing costs and reserves

Lenders want to see that you have cash left over after closing. Closing costs typically run 2 to 5 percent of the loan amount and cover appraisal, title search, underwriting, and other fees. On a $300,000 home with a $60,000 down payment, closing costs might be $5,000 to $8,000.

Many lenders also require you to have 2 to 6 months of mortgage payments in savings after closing. This is called a reserve. If your mortgage payment is $1,500, the lender may want to see $3,000 to $9,000 in the bank after you close. This requirement is stricter for jumbo loans (over $766,550 in most of the country) and for borrowers with lower credit scores or higher debt-to-income ratios.

If you have just enough for a down payment but no reserves, you may not be approved. Saving an extra 3 to 6 months of payments before you apply strengthens your application significantly.

Check what interest rate you would actually receive

Your interest rate depends on your credit score, the loan type, the down payment size, and current market rates. A person with a 750 credit score might receive a rate 0.5 to 1 percent lower than someone with a 650 score on the same loan. The difference in monthly payment is real: on a $250,000 loan, a 0.5 percent rate difference is roughly $130 per month.

You can get a pre-qualification from a lender online in minutes, but it is not binding and does not verify your income or assets. A pre-approval requires you to submit documents (pay stubs, tax returns, bank statements) and gives you a rate lock for 30 to 120 days. Pre-approval is what sellers take seriously and what you need to make an offer.

Shop with at least three lenders. Rates and fees vary, and a difference of 0.25 percent or $500 in closing costs is common. Each lender can pull your credit once within 14 days without it counting as multiple inquiries, so you can compare without damage to your score.

Use a mortgage calculator to model different scenarios

Online mortgage calculators let you enter a home price, down payment, interest rate, and loan term to see the monthly payment. Plug in your actual numbers and see where you land against your 43 percent debt-to-income cap. Then adjust: what if you put down 10 percent instead of 5? What if you paid off your car loan first? What if you waited six months and saved another $10,000?

The calculator shows you the impact of each choice. This is more useful than a generic affordability rule because it reflects your specific income, debts, and goals. You can also see how a 15-year loan (higher monthly payment, less interest paid over time) compares to a 30-year loan.

Remember that the calculator shows the mortgage payment only. Add property taxes, insurance, and HOA fees to get your true housing cost, then check that total against your 28 percent housing ratio.

Know when you are not ready yet

If your debt-to-income ratio is above 43 percent, you will not be approved by conventional lenders, and FHA loans (which allow up to 50 percent) come with mortgage insurance that stays for the life of the loan. The fastest path forward is to pay down existing debt — especially high-interest credit card balances — before you apply. Paying off a $5,000 car loan can lower your ratio by 2 to 3 percent and open up a larger mortgage.

If you have less than 3 percent saved for a down payment, you have options (FHA loans, state first-time buyer programs, down payment assistance), but each comes with trade-offs. FHA loans require mortgage insurance. Down payment assistance programs sometimes come with income limits or restrictions on the neighborhoods where you can buy. Waiting six months to save more gives you more choices and a stronger application.

If you have no credit history or a very low score (below 580), some lenders will not work with you at all. Others charge higher rates. Building credit by becoming an authorized user on someone else's card, paying all bills on time for six months, or using a secured credit card can improve your score enough to lower your rate by 1 to 2 percent.

Frequently Asked Questions

What is the difference between pre-qualification and pre-approval?

Pre-qualification is an estimate based on information you provide; it is not verified and carries no weight with sellers. Pre-approval requires you to submit documents (pay stubs, tax returns, bank statements) and gives you a binding rate lock for 30 to 120 days. Sellers take pre-approval seriously because it means a lender has already verified your income and assets.

Does my credit score matter more than my debt-to-income ratio?

No. Your debt-to-income ratio is the first filter lenders use. A person with a 750 credit score and a 50 percent ratio will be denied, while someone with a 650 score and a 35 percent ratio will likely be approved. Your score affects the interest rate you receive, but your ratio determines whether you are approved at all.

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

No. Lenders count only the income of people whose names will be on the loan. If you are married, both spouses' incomes count. If you are unmarried, only your income counts, even if you share finances. Getting married before you apply increases your combined income and can lower your ratio.

What if my job is commission-based or self-employed?

Lenders typically average your income over the past two years and may require two years of tax returns to verify it. If your income is rising, they use the lower of the two years. If you have been self-employed for less than two years, some lenders will not work with you; others require a CPA letter or additional documentation. Starting the conversation with a lender early gives you time to gather what they need.

Does paying off debt hurt my credit score in the short term?

Paying off debt can lower your score slightly because it changes your credit mix and reduces available credit, but the effect is temporary and small compared to the benefit of lowering your debt-to-income ratio. If you are planning to apply for a mortgage in the next three to six months, focus on paying down balances rather than closing accounts, which preserves your available credit and minimizes score impact.