How Much House Can You Afford?

Before you fall in love with a listing, you need an honest answer to one question: how much house can you actually afford? It's tempting to look at the maximum loan a lender will approve and treat that as your budget. But the amount you can borrow and the amount you should borrow are rarely the same number.

In this guide, you'll learn how lenders judge affordability, how to apply the time-tested 28/36 rule, and how to account for every cost that lands in your monthly payment. We'll work through a real example and show you how a home affordability calculator turns your income and debts into a price range you can trust.

The 28/36 Rule Explained

The 28/36 rule is the foundation of home affordability. It sets two limits based on your gross monthly income—the amount you earn before taxes.

The first number, 28, is your front-end ratio. It says your total housing payment should not exceed 28% of your gross monthly income. The second number, 36, is your back-end ratio: all of your monthly debt payments combined—housing plus car loans, student loans, credit card minimums, and other obligations—should stay at or below 36% of gross income.

For example, if you earn $7,000 per month before taxes, the rule suggests a maximum housing payment of $1,960 (28%) and total debt payments capped at $2,520 (36%). If you already pay $400 toward a car loan, that leaves $2,120 for housing under the back-end limit—so the lower of the two, $1,960, becomes your working ceiling.

These percentages aren't arbitrary. Decades of lending data show that borrowers who stay within these ranges are far less likely to fall behind on payments. Some loan programs allow higher ratios, but the 28/36 rule remains the safest starting point.

How Lenders Judge Your Affordability

When you apply for a mortgage, lenders look at three pillars: your debt-to-income ratio, your down payment, and your credit score.

Your debt-to-income ratio (DTI) is the back-end ratio from the 28/36 rule. Lenders calculate it by dividing your total monthly debt by your gross monthly income. A DTI under 36% is comfortable; many lenders will stretch to 43% or even higher for strong applicants, but a higher DTI means a thinner financial cushion.

Your down payment affects affordability in two ways. A larger down payment reduces the amount you borrow, lowering your monthly payment directly. It also helps you avoid private mortgage insurance (PMI), which lenders typically require when you put down less than 20%. PMI can add $100 to $300 or more to your monthly bill.

Your credit score determines the interest rate you're offered. Borrowers with scores above 760 see the lowest rates, while a score in the 620s can mean a rate one to two percentage points higher. As you'll see below, even a small rate difference changes how much house you can afford by tens of thousands of dollars.

All-In Monthly Costs: PITI and Beyond

A common mistake is to budget only for loan principal and interest. Your real monthly payment is larger. Lenders measure it as PITI:

Principal — the portion that pays down your loan balance
Interest — the cost of borrowing
Taxes — property taxes, usually collected monthly into an escrow account
Insurance — homeowners insurance, and PMI if your down payment is under 20%

On top of PITI, many homes carry HOA fees—monthly dues for condos or planned communities that can range from $50 to several hundred dollars. Lenders include HOA fees when calculating your housing ratio, so you should too.

Property taxes and insurance can easily add 20% to 30% on top of your principal and interest. A $1,600 principal-and-interest payment can become a $2,000+ PITI payment once everything is included. Always budget for the full picture, not just the loan.

A Worked Example

Let's put it together. Suppose you earn $90,000 per year, or $7,500 per month before taxes. You have a $350 monthly car payment and $150 in student loan payments. You've saved $60,000 for a down payment, and your credit score qualifies you for a 6.5% interest rate on a 30-year loan.

Start with the 28/36 rule. Your front-end limit is 28% of $7,500 = $2,100 for housing. Your back-end limit is 36% of $7,500 = $2,700 for all debt; subtract your existing $500 in payments, leaving $2,200 for housing. The binding limit is the lower figure: $2,100 per month for total PITI plus any HOA.

Now reserve part of that $2,100 for taxes and insurance—say $450—leaving about $1,650 for principal and interest. At 6.5% over 30 years, $1,650 per month supports a loan of roughly $261,000. Add your $60,000 down payment, and you're looking at a home price near $321,000.

You can confirm the monthly figure with a mortgage payment calculator, which breaks down exactly how principal, interest, taxes, and insurance combine for any price you're considering.

How Down Payment and Rate Change Your Budget

Two levers move your affordability the most: the size of your down payment and the interest rate.

Suppose, in the example above, you saved $90,000 instead of $60,000. With the same $261,000 loan capacity, your buying power rises to about $351,000—an extra $30,000 in home price, dollar for dollar. A bigger down payment also helps you cross the 20% threshold to drop PMI, freeing up room in your PITI budget for a larger loan.

Interest rates matter just as much. At 6.5%, $1,650 per month supports about $261,000 in borrowing. If rates fall to 5.5%, that same payment supports roughly $291,000—a $30,000 increase without spending an extra dollar each month. If rates climb to 7.5%, your borrowing power drops to about $236,000. This is why improving your credit score before applying can be one of the most valuable steps you take.

Leave Room for Emergencies

Maxing out the 28/36 rule is allowed, but it isn't always wise. Homeownership comes with costs that no calculator prints on a closing statement: a failed water heater, a roof repair, rising property taxes, or a stretch of unemployment.

A healthy approach is to keep your housing payment comfortably below your maximum—closer to 25% of gross income than 28%—and maintain an emergency fund covering three to six months of expenses. Budget separately for maintenance, often estimated at 1% to 2% of the home's value per year. A $320,000 home could need $3,200 to $6,400 annually in upkeep.

Buying a home you can afford with margin to spare protects you when life is unpredictable, and it lets you enjoy the home instead of worrying about every bill.

Key Takeaways

The 28/36 rule sets your baseline: keep housing at or below 28% of gross monthly income and total debt at or below 36%, then use the lower resulting limit as your ceiling.

Lenders weigh three factors—debt-to-income ratio, down payment, and credit score—and each one independently shifts how much you can borrow and at what rate.

Budget for full PITI plus HOA, not just principal and interest; taxes, insurance, and PMI can add 20% to 30% or more to your monthly payment.

Down payment and interest rate are your biggest levers: a larger down payment adds buying power dollar for dollar and can eliminate PMI, while even a one-point rate change can swing your budget by tens of thousands of dollars.

Leave room for the unexpected by staying below your maximum, keeping an emergency fund, and reserving 1% to 2% of the home's value each year for maintenance.

Knowing how much house you can afford turns an overwhelming decision into a clear, confident plan. Run your own numbers through a home affordability calculator, pressure-test them against different rates and down payments, and you'll shop for your next home from a position of strength rather than guesswork.