Ask a mortgage lender how much house you can afford and you will get one answer. Ask your monthly budget the same question and you may get a very different, and smaller, one. The gap between what you can borrow and what you can comfortably live with is where a lot of house-poor homeowners get trapped, stretched thin by a payment that looked fine on a pre-approval letter but leaves nothing for the rest of life. Figuring out a number that actually works starts with a classic guideline called the 28/36 rule, then adjusts for the many costs of ownership that a mortgage quote conveniently leaves out. This guide walks through both, so you can arrive at a price your future self will thank you for.
Start with the 28/36 rule
The most durable rule of thumb for home affordability is the 28/36 rule, a pair of ratios that lenders and financial planners have leaned on for decades. It sets two ceilings, both measured against your gross monthly income (your income before taxes):
- The 28% front-end ratio: no more than 28% of your gross monthly income should go toward housing costs, meaning the full mortgage payment including principal, interest, property taxes, and insurance.
- The 36% back-end ratio: no more than 36% of your gross monthly income should go toward total debt, meaning housing plus all other monthly debt obligations like car loans, student loans, and minimum credit card payments.
Say your household earns $6,000 in gross monthly income. The 28% guideline caps housing at about $1,680 a month, and the 36% guideline caps total debt payments at about $2,160. If you already pay $500 a month toward a car loan and student loans, the back-end limit leaves roughly $1,660 for housing, so your existing debts, not just your income, shape what you can borrow.
This is closely tied to a number lenders scrutinize called your debt-to-income ratio, which compares your monthly debt payments to your gross income. It is worth understanding in its own right, because it drives both how much you qualify for and the rate you are offered; our guide to how lenders judge your debt-to-income ratio breaks it down. The Consumer Financial Protection Bureau explains why lenders weigh it so heavily in its overview of debt-to-income ratio.
Lenders will often approve you for more than the 28/36 rule suggests; many mortgage programs allow a back-end ratio above 40% for well-qualified borrowers. But the rule endures because it builds in breathing room. Borrowing to the absolute maximum a lender allows is how households end up "house-poor," technically able to make the payment but with little left over for saving, emergencies, or simply enjoying life.
What actually makes up a mortgage payment (PITI)
When people picture a mortgage payment, they usually think only of paying back the loan. But a typical monthly payment bundles four things together, known by the shorthand PITI:
- Principal: the portion that pays down the amount you borrowed.
- Interest: the lender's charge for the loan, largest in the early years, as our explainer on how loan amortization works shows.
- Taxes: property taxes assessed by your local government, which vary enormously by location and can climb over time.
- Insurance: homeowners insurance protecting the property against damage.
Lenders usually collect the taxes and insurance portions along with your principal and interest, hold them in an escrow account, and pay those bills on your behalf when they come due. The CFPB explains this arrangement in its description of escrow accounts. The practical consequence is that two homes with identical prices can carry very different monthly payments, because property tax rates and insurance costs differ so much from place to place. When you estimate affordability, you have to price the specific home's taxes and insurance, not just the loan.
The recurring costs a mortgage quote leaves out
PITI is only the beginning. Several ongoing costs rarely appear on a mortgage estimate but hit your budget every month or every year all the same.
Private mortgage insurance (PMI). If you put down less than 20% on a conventional loan, lenders typically require PMI, which protects the lender, not you, if you default. It commonly runs from a fraction of a percent to over one percent of the loan amount per year. The good news is that PMI is not forever: under federal law your lender must automatically cancel it once your loan balance falls to 78% of the home's original value, and you can request cancellation at 80%. The CFPB details your rights in its guide to private mortgage insurance.
Homeowners association (HOA) dues. Condos and many planned communities charge monthly or annual HOA fees for shared maintenance and amenities. These can range from modest to several hundred dollars a month, and they tend to rise over time.
Maintenance and repairs. Unlike renting, no landlord absorbs a failed water heater or a new roof. A common budgeting rule of thumb is to set aside roughly 1% of the home's value each year for maintenance, though older homes can cost more. Building this into a sinking fund for irregular expenses keeps a surprise repair from becoming a crisis.
Utilities and everything else. A larger home usually means larger heating, cooling, water, and electricity bills than an apartment, plus new line items like lawn care, pest control, and higher insurance deductibles after a claim.
| Cost | What it covers | Roughly how it is charged |
|---|---|---|
| Principal & interest | Repaying the loan | Fixed monthly on a fixed-rate loan |
| Property taxes | Local government services | Percentage of assessed value, via escrow |
| Homeowners insurance | Damage to the home | Annual premium, often via escrow |
| PMI | Lender protection if down payment is under 20% | Roughly 0.5% to 1.5% of the loan per year |
| HOA dues | Shared community upkeep | Monthly or annual, set by the HOA |
| Maintenance | Repairs and upkeep | Budget about 1% of home value per year |
Down payment and closing costs: the cash you need up front
Affording the monthly payment is only half the question; you also need cash to get in the door. Two big up-front numbers matter.
The down payment is the share of the purchase price you pay yourself. A 20% down payment is the traditional benchmark because it lets you avoid PMI, but it is far from mandatory: many conventional loans allow as little as 3% down, and government-backed programs allow low or no down payments for eligible buyers. A larger down payment means a smaller loan, a lower monthly payment, and less interest over time; a smaller one gets you into a home sooner but usually costs more each month. If you are still building that fund, our guide on how to save for a down payment can help.
Closing costs are the fees to finalize the loan and transfer the property: lender fees, appraisal, title insurance, prepaid taxes, and more. They typically run about 2% to 5% of the loan amount, due at closing on top of your down payment. The CFPB breaks down exactly what fees are paid at closing and who pays them, and its Owning a Home toolkit provides a standardized Loan Estimate you can use to compare lenders.
One more reserve matters: an emergency fund that survives the move. Draining every dollar for the down payment leaves you exposed the moment something breaks. Keeping a cushion, as our guide to building an emergency fund that holds up explains, is part of buying responsibly, not an optional extra.
Why gross-income rules can overstate what you can afford
Here is the catch buried inside the 28/36 rule: it is measured against gross income, but you pay your mortgage out of take-home pay. After federal and state income taxes, Social Security and Medicare, retirement contributions, and health premiums, your actual spendable income can be 20% to 30% lower than the gross figure the rule uses. A payment that is a tidy 28% of gross might be 35% or more of what actually lands in your bank account.
That is why the smartest move is to sanity-check any lender's number against your real budget. Look at your take-home pay, subtract what you already spend and save, and see what is genuinely left for housing, including all the PITI, PMI, HOA, and maintenance costs above. If you are fuzzy on the difference between gross and net, our guide on how to read your paycheck is a useful companion. A home you can afford on paper but not in practice is not actually affordable.
Putting it together: a realistic affordability check
Turning all of this into a number is less intimidating than it sounds. A sensible sequence looks like this:
- Calculate your gross monthly income and apply the 28/36 rule to get a first-pass ceiling for housing and total debt.
- Subtract your existing debts from the 36% figure to see what is realistically left for a housing payment.
- Build a full PITI estimate for homes in your target range, using that area's actual property tax rate and insurance costs, not national averages.
- Add the extras: PMI if you are under 20% down, HOA dues, and a maintenance reserve of roughly 1% of value per year.
- Check it against take-home pay, not gross, and confirm the total still leaves room for retirement savings, an emergency fund, and normal living.
- Get pre-approved to ground the exercise in real numbers. A mortgage pre-approval tells you what a lender will actually offer and at what rate; just remember the approval amount is a ceiling, not a target.
For a neutral, ad-free walkthrough of the whole process, the CFPB's Owning a Home tools and the federal government's guide to programs that help people buy a home are the best starting points. Run the numbers conservatively, and you will land on a home that fits both your lender's math and your life.
Key takeaways
- The 28/36 rule caps housing at 28% of gross monthly income and total debt at 36%, a conservative guideline that builds in breathing room even when lenders will approve more.
- A mortgage payment is really PITI: principal, interest, property taxes, and homeowners insurance, with taxes and insurance often collected through escrow.
- Budget for the costs a loan quote omits: PMI (if under 20% down), HOA dues, and a maintenance reserve of about 1% of home value per year.
- You need cash up front for a down payment (20% avoids PMI, but lower is possible) and closing costs of about 2% to 5% of the loan, without draining your emergency fund.
- Because the rule uses gross income, always re-check any payment against your take-home pay so you do not end up house-poor.
Frequently asked questions
What is the 28/36 rule for buying a house?
It is a guideline that says your monthly housing costs should stay at or below 28% of your gross monthly income, and your total monthly debt payments (housing plus car loans, student loans, and credit card minimums) should stay at or below 36%. The two ratios correspond to the front-end and back-end debt-to-income ratios lenders evaluate. Many lenders allow higher, but 28/36 is a conservative target that leaves room in your budget.
Does the mortgage payment include property taxes and insurance?
Usually, yes. Most lenders bundle your loan's principal and interest with property taxes and homeowners insurance into a single monthly payment, collectively called PITI, and hold the tax and insurance portions in an escrow account until those bills are due. If your down payment is under 20% on a conventional loan, PMI may be added as well. Always ask a lender for the full PITI figure, not just principal and interest.
How much should I have saved before buying a home?
Enough for three things: your down payment (anywhere from about 3% to 20% or more of the price), closing costs of roughly 2% to 5% of the loan amount, and a retained emergency fund so that a repair or job loss right after moving in does not derail you. Many buyers also keep a small reserve for immediate move-in costs like appliances or minor repairs.
Should I borrow the full amount my lender approves?
Generally, no. A pre-approval reflects the maximum a lender is willing to extend based on your gross income and credit, not the amount that fits comfortably in your real budget. Because the approval is based on gross rather than take-home pay and knows nothing about your personal goals, borrowing well under the maximum is often the wiser and far less stressful choice.
This article is general educational information, not personalized financial, mortgage, or real-estate advice. Loan programs, insurance costs, property tax rates, and qualification rules vary by location and lender and change over time. Verify current figures and your own eligibility with the official sources cited above, including the CFPB, and consider consulting a qualified mortgage professional before making a decision.
