The basic rule: your housing payment should not exceed 28% of your gross monthly income

Start here: take your gross monthly income (the amount before taxes and deductions) and multiply it by 0.28. That number is roughly the maximum monthly payment most lenders will allow for housing costs. This includes your mortgage payment, property taxes, homeowners insurance, and mortgage insurance if you are putting down less than 20%.

This is called the front-end ratio or housing ratio, and it exists because lenders have learned that people who spend more than this tend to fall behind on payments. It is not a law — it is a lending standard that most banks and mortgage companies follow.

Here is a concrete example: if you earn $4,000 gross per month, 28% of that is $1,120. That $1,120 needs to cover your mortgage payment, property taxes, insurance, and any mortgage insurance — all together, not just the mortgage alone.

Key Takeaways

  • Your housing payment (mortgage, taxes, insurance, and mortgage insurance combined) should not exceed 28% of your gross monthly income.
  • Lenders also look at your total debt payments, which should not exceed 36% to 43% of gross income depending on the lender.
  • The actual house price you can afford depends on your down payment, interest rates, and loan term — the same payment buys different house prices under different conditions.
  • Your credit score, savings for a down payment, and existing debts all affect how much a lender will actually offer you, even if the math says you could afford more.
  • Getting pre-approved by a lender tells you what they will actually lend, which is more useful than any calculator because it accounts for your specific situation.

Why 28% matters, and what happens if you go over

The 28% rule exists because housing is usually the biggest expense in a household budget. If you spend more than that on housing, you have less money left for food, transportation, medical care, childcare, and emergencies. When an unexpected expense hits — a car repair, a medical bill, a job loss — people who are already stretched thin on housing are the first to fall behind on their mortgage.

Lenders know this from decades of data. They have learned that borrowers who stay under 28% have much lower default rates. So even if you could technically afford a higher payment, lenders often will not offer it to you.

That said, some lenders will go higher — up to 31% or even 33% — if you have a very strong credit score, significant savings, or a very stable income. But these are exceptions, and the higher you go, the more risk you are taking on.

The second rule: total debt payments should not exceed 36% to 43% of gross income

Lenders do not just look at your housing payment. They also add up every other debt payment you make: car loans, student loans, credit cards, personal loans, and any other monthly obligations. All of these together, plus your housing payment, should not exceed 36% to 43% of your gross monthly income. This is called the back-end ratio or debt-to-income ratio.

This matters because you might pass the 28% housing test but fail the debt test. For example, if you earn $4,000 per month and have $800 in car and student loan payments, your housing payment can only be $640 to stay under a 36% total debt ratio — even though 28% of your income would allow $1,120.

The exact percentage varies by lender. Conventional loans (the most common type) often use 43%. Federal Housing Administration (FHA) loans sometimes go up to 50%, but that is unusual and requires very strong credit.

How down payment and interest rates change what you can afford

The 28% rule tells you what your monthly payment can be, but it does not tell you what house price that translates to. That depends on three things: how much you put down, what interest rate you get, and how long the loan is.

A $1,120 monthly payment on a 30-year loan at 6% interest lets you borrow roughly $187,000. The same $1,120 payment at 5% interest lets you borrow roughly $210,000. A $1,120 payment at 7% interest lets you borrow only about $168,000. Interest rates matter enormously.

Your down payment also matters. If you put 20% down, you avoid mortgage insurance and your payment goes further. If you put 5% down, you pay mortgage insurance on top of your regular payment, which means the same monthly budget buys a less expensive house. The difference can be $50,000 to $100,000 in house price.

Loan term matters too. A 15-year mortgage has a much higher monthly payment than a 30-year mortgage for the same loan amount, so the same monthly budget buys a cheaper house on a 15-year term.

What lenders actually look at beyond the percentages

The 28% and 36% rules are starting points, not the whole story. Lenders also examine your credit score, your savings and down payment, your employment history, and the type of loan you are seeking.

A credit score below 620 makes it very hard to get a conventional loan at all, and you may be steered toward FHA loans with higher costs. A credit score above 740 opens access to better interest rates and sometimes more flexible debt ratios. A down payment of 20% or more is treated very differently from a down payment of 3% to 5%.

Employment history matters too. If you have been in the same job for two years or more, lenders see you as stable. If you just changed jobs, even to a better one, some lenders will not count that income yet. Self-employed people face extra scrutiny and usually need two years of tax returns.

The type of loan also changes what you can afford. Conventional loans (sold to Fannie Mae or Freddie Mac) follow the 43% rule strictly. FHA loans are more flexible on debt ratios but charge mortgage insurance for the life of the loan. VA loans (for military members and veterans) have no down payment requirement but have their own limits.

Getting pre-approved shows you what you can actually afford

Calculators and rules of thumb are useful, but they do not account for your specific situation. The only way to know what you can actually afford is to get pre-approved by a lender. Pre-approval means a lender has looked at your credit, income, debts, and savings and told you in writing how much they will lend you.

Pre-approval is free and takes a few days. You will need to provide recent pay stubs, tax returns (usually two years), bank statements, and a list of your debts. The lender will pull your credit report and calculate your debt-to-income ratio based on your actual numbers.

Pre-approval is different from pre-qualification, which is just a rough estimate based on what you tell them over the phone. Pre-approval is what real estate agents and sellers take seriously, and it is what you need before you start house hunting.

Common mistakes that reduce how much you can afford

High credit card balances hurt you even if you pay them on time. Lenders count the minimum payment on credit cards as a debt obligation, not the balance you actually owe. A credit card with a $10,000 balance might count as a $200 monthly obligation, which reduces your housing budget.

Recent hard inquiries on your credit report (from explore for credit) can lower your score slightly and make lenders nervous. Avoid explore for new credit cards or loans in the months before you explore for a mortgage.

Changing jobs or taking a new job right before explore for a mortgage can disqualify you or force you to wait. Many lenders want to see two years of stable employment history. If you just changed jobs, wait at least 30 days and bring documentation that your new income is the same or higher.

Co-signing a loan for someone else counts as your debt, even if they make the payments. If you are thinking about buying a house soon, avoid co-signing anything.

What happens if the math says you can afford more than feels comfortable

Just because a lender will lend you $400,000 does not mean you should borrow it. The 28% rule is a ceiling, not a target. Many financial advisors suggest aiming for 20% to 25% of gross income instead, which gives you more breathing room for emergencies and other goals like retirement savings.

Think about your actual life, not just the numbers. Do you have a stable job with good job security, or is your industry volatile? Do you have three to six months of expenses saved, or are you living paycheck to paycheck? Do you have kids, aging parents, or health issues that might create unexpected costs? Do you want to travel, take classes, or save for retirement?

A house payment that is technically affordable can still be a bad choice if it leaves you with no margin for error. The goal is to own a home without it owning you.

Frequently Asked Questions

Does my student loan debt count against me when I explore for a mortgage?

Yes. Lenders add your student loan payment to your total debt obligations, even if you are on an income-driven repayment plan. If you are not currently making payments because you are in school or on a deferment, lenders may still count an estimated payment based on your loan balance. This can significantly reduce your housing budget.

What if I have a co-signer — does that change what I can afford?

A co-signer with strong income and low debt can help you borrow more, but the lender will still look at your own debt-to-income ratio first. A co-signer does not erase your debts from the calculation; they just add their income to the mix. This helps most when you have low income but good credit and low debt.

Can I afford a house if I am self-employed?

Yes, but lenders require more documentation. You will need two years of tax returns, and lenders will average your income over those two years. If your income is growing, they may use the lower year. Some lenders also require a CPA letter confirming your income. Self-employed borrowers often may have access to for less than W-2 employees with the same gross income.

Does getting pre-approved lock me into a specific interest rate?

No. Pre-approval usually comes with a rate lock period of 30 to 60 days, but that is optional. You can shop for rates after pre-approval, and different lenders will offer different rates. Getting pre-approved by multiple lenders (within a two-week window) lets you compare rates without hurting your credit score.

What if my income varies month to month?

Lenders will average your income over the past two years if you are self-employed or work on commission. If you are salaried but receive bonuses, they may count the bonus only if you have received it for two years in a row. Seasonal workers face the same two-year requirement. If your income is new or inconsistent, lenders may not count it at all.