What a mortgage lender will lend you versus what you can actually pay

A lender will tell you the maximum they will lend based on your income and credit score. That number is almost always higher than what you should actually borrow. The difference between what you can get approved for and what you can afford is the most important gap in home buying.

Lenders use two main ratios to decide how much to lend. The front-end ratio (also called the housing ratio) caps your monthly mortgage payment at 28% of your gross monthly income. The back-end ratio (also called the debt-to-income ratio) caps your total monthly debt payments—including the mortgage, car loans, credit cards, and student loans—at 36% to 43% of gross income, depending on the lender and loan type.

These ratios exist because they predict default risk, not because they leave you money to live on. A lender does not care whether you can pay your electric bill or buy groceries. You do.

Key Takeaways

  • Lenders typically approve you for 28% of gross income as a monthly mortgage payment, but this leaves little room for property taxes, insurance, and maintenance.
  • Your actual affordable mortgage depends on your down payment size, local property taxes and insurance costs, how much non-mortgage debt you carry, and your monthly expenses outside housing.
  • A common rule of thumb is to spend no more than 25% to 28% of your gross monthly income on the total housing payment, not just the loan itself.
  • The monthly cost of homeownership includes principal and interest, property taxes, homeowners insurance, HOA fees if applicable, and maintenance reserves—not just the mortgage payment.
  • Working backward from your actual monthly budget is more reliable than working forward from a lender's approval amount.

The real monthly cost of a mortgage payment

When you see a mortgage payment quoted, it often shows only principal and interest. The actual amount that leaves your bank account each month is much larger. This combined payment is called PITI: principal, interest, taxes, and insurance.

On a $300,000 mortgage at 7% interest over 30 years, the principal and interest alone is roughly $2,000 per month. But if your property taxes are $200 per month and homeowners insurance is $150 per month, your actual payment is $2,350. If you put down less than 20%, you also pay private mortgage insurance (PMI), which can add $150 to $300 per month depending on your loan size and down payment percentage.

If your home is in a planned community or has a shared roof or structure, you may also owe a monthly homeowners association (HOA) fee, which ranges from $50 to several hundred dollars. None of these costs show up in the principal-and-interest number a lender quotes you.

Beyond the monthly payment, homeownership has costs that do not appear on a mortgage bill. Maintenance and repairs average 1% of the home's purchase price per year—so a $300,000 home should have roughly $3,000 set aside annually for roof repairs, HVAC replacement, plumbing, and other upkeep. Divide that by 12 and add it to your monthly budget.

Working backward from your actual budget

The most honest way to find your affordable mortgage is to start with your take-home pay and your actual monthly expenses, then see what is left for housing.

Write down your monthly gross income (before taxes). Subtract federal income tax, Social Security, Medicare, state tax, and any other payroll deductions to find your actual take-home pay. Then list every monthly expense: groceries, utilities, car payment, car insurance, gas, phone, internet, childcare, student loans, credit card payments, medical costs, and anything else you spend money on regularly. Add a line for savings—even $200 per month matters.

The amount left over is what you have for housing. If you have $4,000 in take-home pay and $2,500 in other expenses, you have $1,500 for housing. That $1,500 must cover principal, interest, property taxes, insurance, PMI if applicable, HOA fees if applicable, and your maintenance reserve.

This method is slower than plugging numbers into a lender's calculator, but it reflects your actual life. A lender's approval is based on ratios that work for people with no other financial obligations. You are not that person.

How down payment size changes what you can afford

The larger your down payment, the smaller your monthly payment—but the relationship is not linear. A 10% down payment versus a 20% down payment does not just lower your payment by 10%. It also eliminates PMI, which can save $150 to $300 per month on a typical loan.

On a $300,000 home, a 10% down payment is $30,000, leaving a $270,000 loan. A 20% down payment is $60,000, leaving a $240,000 loan. The difference in principal is $30,000, which lowers your monthly payment by roughly $200. But removing PMI saves another $200 to $300 per month. The total monthly savings from that extra $30,000 down is $400 to $500.

This means if you are deciding between a $300,000 home with 10% down and a $250,000 home with 20% down, the monthly payment difference may be smaller than you expect. Conversely, if you have a choice between saving for a larger down payment or buying sooner with a smaller one, the monthly cost difference is worth calculating precisely for your situation.

Down payment size also affects your interest rate. Borrowers with 20% or more down typically receive lower rates than those with less. A 0.5% difference in interest rate changes your monthly payment by roughly $150 on a $240,000 loan, so the down payment affects both the loan size and the rate you pay on it.

Property taxes and insurance vary by location

Two identical homes in different states can have vastly different total monthly costs because property taxes and insurance are local. A $300,000 home in a low-tax state might have $150 per month in property taxes, while the same home in a high-tax state could be $400 per month.

Before you decide what price range you can afford, find out the property tax rate in the specific area where you are looking. Most county assessor websites publish tax rates by neighborhood. Multiply the home price by the local tax rate to estimate your annual tax bill, then divide by 12.

Homeowners insurance also varies by location, home age, and local risk factors like flood zones or wildfire areas. A home in a flood zone or coastal hurricane area costs significantly more to insure than an identical home 20 miles inland. Get insurance quotes for the specific neighborhoods you are considering, not just a state average.

How existing debt affects your mortgage approval and affordability

If you carry credit card balances, car loans, or student loans, they reduce the mortgage amount a lender will approve. A lender looks at your total monthly debt payments, not just the mortgage. If you owe $500 per month on a car and $200 per month on student loans, that $700 counts against your debt-to-income ratio before the mortgage is even added.

On a $5,000 gross monthly income, a 43% debt-to-income limit means your total debt payments can be $2,150. If you already owe $700 per month, you have only $1,450 left for a mortgage payment. That $1,450 must cover principal, interest, taxes, insurance, and PMI—leaving little room for a large loan.

Paying down or eliminating non-mortgage debt before you buy increases your mortgage approval amount and your actual affordability. Paying off a $200 car payment frees up $200 per month that can go toward housing. This is one of the few levers you control before you apply.

The difference between approval and comfort

A lender will approve you for a mortgage that uses 43% of your gross income for all debt. That does not mean you should take it. Many financial advisors recommend keeping your total housing payment—including taxes, insurance, and maintenance—to 25% to 28% of gross income, leaving more room for emergencies, savings, and life changes.

The difference between a 43% debt-to-income ratio and a 28% housing-to-income ratio is significant. On $5,000 gross monthly income, 43% of total debt is $2,150. A 28% housing ratio is $1,400. That $750 difference is the cushion between "approved" and "comfortable."

Life happens. Your income may drop. Your heating system may fail. Your child may need braces. A mortgage that leaves you no margin for error will feel like a trap within a few years. Borrow less than the maximum, even if a lender says you can afford more.

Frequently Asked Questions

What if I have a large down payment but low income?

A large down payment lowers your monthly payment but does not change your income. Lenders still use your income to decide how much to lend. If your income is $3,000 per month, a lender will not approve a $400,000 mortgage even if you have $200,000 to put down, because the monthly payment would exceed their income ratios. You can afford a smaller home than someone with higher income, regardless of down payment size.

Does my credit score affect how much I can borrow?

Credit score affects the interest rate you receive and whether you are approved at all, but not the maximum loan amount directly. A lower credit score means a higher interest rate, which increases your monthly payment on the same loan size. A higher rate makes a large loan unaffordable even if the lender technically approves it. Better credit means lower rates and more purchasing power.

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

Online calculators show you what lenders typically approve based on income and debt ratios. A lender can give you a more precise number based on your actual credit score, employment history, and the specific loan program you may have access to for. Use a calculator to get a rough range, then talk to a lender to see your actual approval amount. But remember: approval is not the same as affordability.

What if my spouse and I have very different incomes?

Lenders can count both incomes on a joint application. Your approval is based on combined gross income and combined debt. If one spouse earns $6,000 per month and the other earns $2,000, your combined income is $8,000. However, if one spouse loses their job, you need to be able to afford the mortgage on the remaining income alone. Plan conservatively.

Can I afford a more expensive home if I wait and save more?

Yes, in two ways. A larger down payment lowers your monthly payment and eliminates PMI. Paying off existing debt increases your debt-to-income capacity. If you can save an extra $50,000 and pay off a $300 car payment, your approval amount and actual affordability both increase significantly. The time spent saving often pays for itself in lower rates and lower monthly costs.