Start with what you can put down and what you can borrow

How much house you can afford depends on three things: how much cash you have for a down payment, how much monthly debt payment a lender will allow you, and the interest rate you may have access to for. Most people start by figuring out their down payment, then work backward to see what loan amount that supports, then forward to see what monthly payment that loan creates.

A lender will not lend you money based on how much you want to spend. They lend based on what your income can support. The standard rule is that your total monthly debt payments—including the new mortgage, property taxes, insurance, and any car loans, student loans, or credit card minimums you already have—should not exceed 43% of your gross monthly income. Some lenders will go to 50% if you have a strong credit score and savings, but 43% is the number to plan around.

This means if you earn $5,000 per month before taxes, a lender will typically allow you to carry about $2,150 in total monthly debt. If you already owe $300 on a car loan and $150 on student loans, you have $1,700 left for a mortgage payment, property taxes, homeowners insurance, and mortgage insurance if your down payment is less than 20%.

Key Takeaways

  • Lenders typically cap your total monthly debt payments at 43% of your gross income, which is the real ceiling on what you can borrow.
  • Your down payment size affects both the loan amount you need and whether you pay mortgage insurance, so a larger down payment lowers your monthly cost.
  • Property taxes and homeowners insurance vary by location and can add $300 to $800 per month to your housing cost, so you must research your specific area.
  • The interest rate you may have access to for depends on your credit score, debt-to-income ratio, and the current market, so getting pre-approved shows you the real number.
  • A mortgage calculator can show you what monthly payment a given loan amount creates, but only a lender can tell you what loan amount you actually may have access to for.

How your down payment size changes what you can afford

The larger your down payment, the smaller the loan you need, and the smaller your monthly payment. But down payment size also affects whether you pay mortgage insurance—an extra monthly fee that protects the lender if you default.

If you put down less than 20% of the home's price, you will pay mortgage insurance. The amount varies by lender and your credit score, but it typically runs 0.5% to 1.5% of the loan amount per year, added to your monthly payment. On a $300,000 loan, that could be $125 to $375 per month. If you put down 20% or more, you avoid this fee entirely.

This means a $50,000 down payment on a $250,000 home (20% down) creates a very different monthly cost than a $25,000 down payment on the same home (10% down). The second scenario requires a larger loan and includes mortgage insurance, so your payment could be $200 to $300 higher each month. Over 30 years, that adds up to tens of thousands of dollars.

Property taxes and insurance are part of your housing cost, not separate

When you calculate what you can afford, many people focus only on the mortgage payment itself. That is a mistake. Your actual monthly housing cost includes the mortgage payment plus property taxes, homeowners insurance, and mortgage insurance if applicable. All of these together must fit within your 43% debt-to-income limit.

Property taxes vary wildly by location. In some states and counties, property tax is 0.3% of the home's value per year. In others, it is 1.5% or higher. A $300,000 home in a low-tax area might cost $75 per month in property tax. The same home in a high-tax area might cost $375 per month. You must research the specific county or municipality where you are looking to buy, because this number directly affects affordability.

Homeowners insurance also varies by location, home age, and coverage level, but typically runs $100 to $300 per month. Homes in flood zones, wildfire zones, or areas with high crime or weather risk cost more to insure. If you are considering homes in different areas, get insurance quotes for each one before deciding what you can afford.

Get pre-approved to learn your actual borrowing limit

A pre-approval is a letter from a lender stating how much they will lend you based on your income, credit score, and debts. It is not a may provide—the lender will verify everything again when you make an offer—but it shows you the real number, not a theoretical one.

To get pre-approved, you will need to provide recent pay stubs, tax returns from the past two years, bank statements showing your down payment savings, and a list of your debts (car loans, student loans, credit cards). The lender will pull your credit report and calculate your debt-to-income ratio. They will tell you the maximum loan amount they will offer and at what interest rate.

The interest rate matters enormously. A 1% difference in rate changes your monthly payment by roughly $250 per $100,000 borrowed. If you are pre-approved at 7% but rates drop to 6%, your payment drops. If rates rise to 8%, your payment rises. You cannot lock in a rate until you make an offer on a specific home, but the pre-approval shows you what rate you currently may have access to for based on your credit and finances.

Use a mortgage calculator to see the monthly payment for different loan amounts

Once you know your pre-approval amount and interest rate, a mortgage calculator shows you what the monthly payment will be. You enter the loan amount, interest rate, and loan term (usually 30 years), and it calculates the payment. Most calculators also let you add property tax and insurance estimates to show your total monthly housing cost.

The calculator shows you the math, but it does not tell you what you can afford—your lender already did that. What it does is let you see the trade-offs. If you want to buy a $350,000 home but your pre-approval is for $300,000, the calculator shows you that you would need a $50,000 down payment instead of $25,000 to make it work. Or it shows you that if you buy a $300,000 home instead, your payment drops by $400 per month, freeing up money for other expenses.

Do not use a calculator to override your pre-approval limit. A calculator cannot see your full financial picture the way a lender can. If a calculator says you can afford a $500,000 home but your lender pre-approved you for $350,000, the lender's number is the real one.

Account for closing costs and moving expenses in your budget

The price of the home is not the only money you need. Closing costs—fees paid to the lender, title company, and other parties when you buy—typically run 2% to 5% of the loan amount. On a $300,000 loan, that is $6,000 to $15,000. Some of this can be rolled into the loan, but if you pay it upfront, it comes out of your savings.

You will also need money for inspections, appraisals, and homeowners insurance before closing. After you move in, you may need repairs, new appliances, or furniture. If you are stretching to afford the down payment and closing costs, you have no cushion left for these expenses.

A practical rule is to keep at least 3 to 6 months of your new mortgage payment in savings after closing, in case you lose income or face an unexpected repair. If your mortgage payment will be $1,500, keep $4,500 to $9,000 in reserve. This is separate from your down payment and closing costs.

Consider what happens if interest rates or your income changes

Your pre-approval is based on today's interest rate and your current income. If rates rise before you close, your payment rises. If you lose your job or take a pay cut, your ability to pay drops. Neither of these changes your pre-approval letter, but both change your real situation.

When you decide what to offer on a home, leave room for these possibilities. If your pre-approval allows you to borrow $350,000, consider whether you can still afford the payment if rates rise 1% or if your income drops 10%. If the answer is no, borrow less. A home you can afford in good times and bad is a home you can actually afford.

Also remember that property taxes and insurance can rise over time. A home that costs $1,500 per month today might cost $1,700 per month in five years. Your income may rise too, but do not count on it. Budget for the possibility that your housing cost will increase.

Frequently Asked Questions

What if I have student loans or credit card debt? Does that reduce how much I can borrow?

Yes. Your lender counts all monthly debt payments toward your 43% limit, including student loan minimums and credit card minimums. If you owe $300 per month on student loans and $150 on credit cards, you have $450 less available for a mortgage payment. Paying down these debts before buying increases your borrowing power.

Can I afford a home if I am self-employed or have irregular income?

Yes, but lenders require more documentation. Most will average your income over two years and may require two years of tax returns plus profit-and-loss statements. Some require a larger down payment or charge a higher interest rate. Get pre-approved early to see what documentation your lender needs.

What if I want to put down more than 20%? Does that change what I can afford?

A larger down payment lowers your monthly payment and eliminates mortgage insurance, so you can afford a more expensive home with the same monthly payment. It also reduces your risk if the home value drops. The trade-off is that the money in your down payment is not available for other uses or emergencies.

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

Talk to a lender first. A calculator shows you the math, but only a lender can tell you what you actually may have access to for based on your credit, income, and debts. A pre-approval takes a few days and is free. Once you have that number, a calculator becomes useful for exploring options within your real limit.

What if the home I want costs more than my pre-approval allows?

You have three options: increase your down payment, look at less expensive homes, or improve your finances before buying. Improving your finances means paying down debt, raising your income, or saving a larger down payment. Stretching beyond your pre-approval to buy a home you cannot afford is how people end up in financial trouble.