The mortgage you can afford depends on your income, debts, and down payment, not on what a lender will approve

A lender will often approve you for more than you should borrow. Banks use a formula: they will lend you up to 28% of your gross monthly income for housing costs (mortgage, taxes, insurance), or up to 36% if you have few other debts. But that formula protects the bank, not you. Your actual affordability depends on what you can pay month after month without cutting into savings, retirement contributions, or emergency funds.

The most useful number to start with is your gross monthly income — your pay before taxes. From there, you work backward: decide what percentage of that income you are willing to spend on housing, then calculate the mortgage payment that fits. Most financial advisors suggest keeping housing costs between 25% and 28% of gross income, which is tighter than what lenders allow. This leaves room for property taxes, insurance, and maintenance without squeezing your other financial goals.

Key Takeaways

  • Lenders will approve you for more than you should borrow; their 28% to 36% formula protects their risk, not your budget.
  • A safer target is 25% to 28% of your gross monthly income for all housing costs combined (mortgage payment, property taxes, homeowners insurance).
  • Your down payment size directly shrinks the loan amount you need and lowers your monthly payment, so saving more upfront reduces long-term cost.
  • Existing debts (car loans, student loans, credit cards) reduce the mortgage amount lenders will approve, and they should reduce what you actually borrow.
  • Property taxes and insurance vary by location and home price, so get a quote for your specific area before deciding on a price range.

Calculate your housing budget from your income

Start with your gross monthly income — the number before taxes, retirement contributions, or health insurance come out. If you earn $60,000 per year, your gross monthly income is $5,000. At 28% of that, your total housing budget is $1,400 per month.

That $1,400 covers the mortgage payment itself, property taxes, homeowners insurance, and mortgage insurance (if your down payment is less than 20%). It does not cover utilities, maintenance, or repairs. Once you know your total housing budget, subtract the estimated property taxes and insurance for homes in your price range. What remains is what you can spend on the actual mortgage payment.

Property taxes and insurance vary widely by location and home value. In some counties, property tax runs 0.5% of the home's value per year; in others it is 1.5% or higher. Homeowners insurance ranges from $800 to $2,000 per year depending on the home and location. Contact a local insurance agent and your county assessor's office to get real numbers for the area where you want to buy, rather than guessing.

How your down payment changes what you can afford

A larger down payment shrinks the loan amount you need, which lowers your monthly payment and eliminates mortgage insurance. If you are buying a $300,000 home with a 3% down payment, you borrow $291,000. With a 20% down payment, you borrow $240,000. The difference in monthly payment is roughly $300 to $400, depending on interest rates.

Mortgage insurance (PMI) is required when your down payment is less than 20%. It typically costs 0.5% to 1.5% of the loan amount per year, added to your monthly payment. On a $291,000 loan, that is $120 to $360 per month. You can remove PMI once you reach 20% equity in the home, but that takes years. Saving for a larger down payment upfront is almost always cheaper than paying PMI.

The trade-off is timing: if you wait years to save 20% down, you may miss the chance to buy when prices or rates are favorable. A 10% down payment with PMI might cost less overall than waiting two more years and paying higher prices. Run the numbers for your situation: calculate the total cost of buying now with PMI versus waiting and buying later with a larger down payment.

How existing debts reduce your borrowing power

Lenders look at your debt-to-income ratio (DTI): the percentage of your gross monthly income that goes to debt payments. This includes car loans, student loans, credit card minimums, and the new mortgage payment. Most lenders will not approve a mortgage if your total DTI exceeds 43%, though some will go to 50% if you have a large down payment and excellent credit.

If you earn $5,000 per month and already pay $800 in car and student loans, your remaining debt budget is $1,350 (at 43% DTI). Subtract the estimated property taxes and insurance, and you have even less left for the mortgage payment. Paying down existing debts before you buy increases the mortgage amount you can afford without changing your income.

This is one reason to prioritize paying off car loans or credit cards before applying for a mortgage. Eliminating a $300 monthly car payment directly frees up $300 in borrowing power. The same applies to student loans: if you are on an income-driven repayment plan, your monthly payment is lower, which helps your DTI, but the full loan balance still counts against you in some lenders' calculations.

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

Lenders approve based on income and credit, not on your actual expenses. They do not know whether you have children, aging parents, medical costs, or plans to change jobs. They do not account for the fact that homeownership costs more than rent: property taxes, insurance, maintenance, repairs, and utilities are your responsibility, not a landlord's.

A useful rule is to keep your mortgage payment (not total housing costs) to no more than 20% to 22% of gross income. This leaves room for property taxes, insurance, maintenance, and the rest of your budget. If you earn $5,000 per month, that is a mortgage payment of $1,000 to $1,100. At current interest rates, that payment supports a loan of roughly $180,000 to $200,000, depending on the rate and loan term.

That is often less than what a lender will approve. The gap between approval and affordability is where your financial safety lives. Staying below what you are approved for means you can handle a job loss, a medical emergency, or a major home repair without defaulting on the loan.

Use a mortgage calculator to test different scenarios

Online mortgage calculators let you enter a loan amount, interest rate, and loan term (usually 15 or 30 years) to see the monthly payment. You can also work backward: enter your target monthly payment and see what loan amount it supports. Most calculators include fields for property taxes and insurance, so you can see your total housing cost, not just the mortgage payment.

Test multiple scenarios: What if interest rates rise? What if you put down 10% instead of 20%? What if you buy a home $50,000 cheaper? Seeing how each change affects your payment helps you understand the trade-offs and find a price range that fits your actual budget, not just the lender's formula.

Keep a spreadsheet of your results. Include the home price, down payment amount, loan amount, interest rate, property tax estimate, insurance estimate, and total monthly housing cost. This becomes your reference when you are shopping and a real estate agent suggests a home above your range.

What to do if you cannot afford what you want to buy

If homes in your area are priced above what your income supports, you have a few paths. The first is to save a larger down payment, which reduces the loan amount and monthly payment. The second is to improve your income: a raise, a second job, or a spouse's income all increase your borrowing power. The third is to wait: if you are early in your career, your income will likely rise, and you may be able to afford more in a few years.

The fourth option is to buy a less expensive home now and upgrade later. A $250,000 home with a 20% down payment costs less per month than a $350,000 home with 5% down, even though the second home is more expensive. Building equity in the cheaper home for five years, then selling and buying up, is often cheaper than stretching to buy the dream home immediately.

The option to avoid is borrowing from family, taking out a personal loan to boost your down payment, or co-signing with someone whose income you cannot verify. These tactics hide your true debt load and can leave you unable to pay if circumstances change.

Frequently Asked Questions

Can I use my spouse's income if we file taxes separately?

Yes, but only if you both apply for the mortgage together and both are on the loan. If you apply alone, only your income counts. Some lenders require both spouses to be on the loan if you are married, even if one spouse has no income. Check with your lender about their policy before you start house hunting.

What if my income varies month to month?

Lenders typically average your income over the past two years for self-employed people or those on commission. They may use your lowest month or a conservative average. Document your income with tax returns, profit-and-loss statements, or bank deposits. The more stable your income history looks, the more a lender will approve.

Does getting pre-approved mean I can actually afford that amount?

No. Pre-approval means a lender will lend you that amount based on your income and credit, not that you should borrow it. Pre-approval uses the lender's formula (28% to 36% of income), which is designed to protect the lender's risk, not your budget. Use your own calculation (25% to 28% of income) to decide what you can actually afford.

Should I pay off my student loans before buying a house?

Not necessarily. If your student loan payment is low and your income is stable, keeping the loan and buying sooner may be better than waiting years to pay it off. However, if your monthly payment is high relative to your income, paying it down first increases your borrowing power. Run the numbers both ways: buy now with the loan, or wait and buy later without it.

What if interest rates drop after I lock in my rate?

You cannot lower your rate after closing unless you refinance, which costs money and takes time. Some lenders offer a "rate lock" period (usually 30 to 60 days) that lets you lock in a rate before closing. If rates drop during that period, you can ask to refinance, but the lender is not required to agree. Refinancing makes sense only if rates drop enough to offset the closing costs, usually at least 0.5% to 1%.