When it comes to homebuying, everyone knows the critical rule: Don't purchase more house than you can afford. Budgeting for a home can be done. But what constitutes "affordable" will differ from one buyer to the next. As of the fourth quarter of 2021, the median sales price for a new home was nearly $$361,700, which means that some folks pay a lot more than that, and others a lot less.1

Wherever you fall on the spectrum, a home will probably be one of the most significant single purchases you'll ever make. However, figuring out the sweet spot of affordability requires more than getting a pre-approval letter from a mortgage lender.

First-time buyers tend to shop on the amount a lender is willing to advance them, not considering other expenses. This can set them up for financial hardship and even a potential foreclosure if they can't afford the monthly payment.

The 28% Rule Can Get You Started

One of the easiest ways to calculate your homebuying budget is the 28% rule, which dictates that your mortgage shouldn't be more than 28% of your gross income each month. The Federal Housing Administration (FHA) is a bit more generous, allowing consumers to spend as much as 31% of their gross income on a mortgage.2 But don't forget that if you have other debts, you must consider them in addition to the mortgage payment to determine how much you can genuinely afford.

Mortgage lenders look at a prospective borrower's debt-to-income ratio when determining if they will lend money. Let's say your monthly mortgage payment is $1,000 a month, and your other expenses are $1,000, so overall, your monthly financial obligations come to $2,000. Now let's say you have a gross monthly income of $6,000, which puts your debt-to-income ratio at 33%, which may be too high.

Generally, the highest debt-to-income ratio a borrower can have and get a mortgage from a qualified lender.3

Homeowning Expenses Beyond the Mortgage

Getting preapproved for a home loan is an essential first step in the homebuying process, but it is only one consideration. A mortgage isn't the only recurring expense: homeownership comes with many other ongoing costs, which buyers need to anticipate. These include homeowners' insurance, utilities, repairs, and maintenance costs. Maintenance alone can add up: The lawn needs to be cut, the snow must be shoveled, and the leaves raked. Buyers also need to consider property taxes.

These expenses can add significantly to your monthly outlays, making a home that seemed affordable on paper pricey in reality. So you should include all of these costs and other regular expenses when determining how much home you can afford. A $1,500-per-month mortgage payment may be palatable, but add $1,500 in monthly expenses, and suddenly your obligations have doubled.

Your Down Payment Should Dictate the Purchase

Generally, lenders want homebuyers to pay at least 20% of the purchase price in cash. If they can only make a down payment below that amount, they can still get a mortgage but often must also shoulder the extra expense of private mortgage insurance (PMI).5 Paying PMI means their monthly mortgage payment will go up by anywhere from 0.5% to 1% of the loan amount.

How much you pay in PMI will depend on the size of the home, your credit score, and the potential for the property to appreciate, among other things. If you can't swing $60,000 down on a $300,000 home, shoot for at least 10%. The more down payment, the less interest you'll pay over the life of the loan, and the smaller your monthly mortgage payment will be, even if you are hit with mortgage insurance.

The amount you saved for the down payment should also influence the house you buy. If you have enough to put 20% on one home but 10% on another, the cheaper home will give you more bang for your buck.

Buyers also need to set aside closing costs, which can amount to between 2% and 5% of the purchase price, depending on which state you live in.6 If you purchase a $200,000 home, you could pay between $4,000 and $10,000 in closing costs alone. The less you have to finance the loan, the lower interest you will pay over the life of the loan, and the sooner you'll see a return on your investment.

Choose a Property You Can Handle

When considering the affordability of a home, first-time buyers need to consider the condition and size of the property. After all, large isn't always good, especially if heating and cooling break your budget. A quaint home sitting atop a picturesque hill may be a dream come true, but shoveling that long, steep driveway during the winter months could be a costly nightmare. So could that 3,000-square-foot fixer-upper, which seems super cheap until you realize that you need to renovate every room in the house.

Look at utility bills for the properties you're considering—and have a construction expert estimate what fixing it up could cost. If you're planning to do it mostly yourself, be realistic about what you can handle, both in skill sets and time.

The Bottom Line

Homeownership is still the American dream, but it can quickly become a nightmare if you miscalculate your purchase and don't make a smart financial plan. First-time buyers, in particular, have a lot of wants, often more than they can handle. They must make sure that the house they purchase is affordable by considering more than just the monthly mortgage payment.

Without some upfront calculations, they can find themselves house-rich but cash-poor, leading to all sorts of financial pain. Take time to cost out your dream before you sign for it.