Six months ago, the bank told me I could buy a $480,000 house. That number felt fantastic for about a week. Then I did the math myself and discovered the monthly payment on that house would leave me with roughly $210 a month once utilities, groceries, and student loans were paid. I backed down to a townhouse at $312,000, and my only regret is not checking earlier.
How much house can you really afford? The answer depends on much more than your annual salary. A lender’s pre-approval is based on gross income, current debts, and an assumption about how much you should spend on housing. You live on net income, and your life is not an assumption. The steps below look at the numbers that actually decide whether a mortgage is a comfort or a weight.
Start With the 28/36 Rule, But Treat It as a Warning, Not a Green Light
Most mortgage lenders look at two ratios. Your front-end ratio is your planned housing payment divided by your gross monthly income. Your back-end ratio adds in minimum monthly payments on credit cards, student loans, car loans, and child support. The classic standard is 28% of gross income for housing and 36% for total debt. Qualified mortgage rules often allow a back-end ratio up to 43%, and some lenders will stretch to 45% or even 50% with excellent credit.
Here is why those numbers can fool you: they use gross income, so a $100,000 salary means $8,333 a month on paper. But after federal tax, state tax, Social Security, Medicare, health insurance, and a 6% retirement contribution, take-home pay in a medium-tax state is closer to $5,600. That is a gap of over $2,700. The 28% threshold on gross income allows a $2,333 monthly housing payment. On take-home pay, that equals 42% of what actually lands in your bank account.
What 36% Really Feels Like in Cash
Use a concrete example. You earn $84,000 a year. Your lender sees $7,000 a month in gross income and allows $2,520 for total debt at 36%. You already have a $380 student loan, a $260 car payment, and $80 of minimum credit card charges. That leaves $1,800 for a mortgage payment. On your paychecks, you bring home about $4,400. After those debts, you have $3,680. If you have been spending $2,400 on rent, utilities, food, and transportation, a $1,800 mortgage leaves you $1,880. That looks fine until maintenance, a medical bill, or brake repair shows up.
The Down Payment Is Only the First Lump Sum
Many first-time buyers save for a 20% down payment and then discover the purchase comes with a second set of costs. On a $350,000 home, a 20% down payment is $70,000. What gets forgotten is the rest.
Closing costs often run $7,000 to $14,000 on that same purchase, depending on your lender, county, and whether the seller covers part. An appraisal runs $400 to $800. A general inspection runs $300 to $600. A sewer line scope can cost $200 to $400. Moving a household costs $500 to $2,000 if you hire professional movers. And in the first month, most buyers buy locks, smoke detectors, and a doormat.
Don’t Forget Mortgage Insurance
If you put down less than 20%, you pay mortgage insurance. On a conventional loan, private mortgage insurance, or PMI, might cost $150 to $300 a month on a $300,000 loan. On an FHA loan, mortgage insurance premiums are higher and can last for the life of the loan if you put down less than 10%. This monthly charge lowers the price you can afford, not just your pride.
Property Taxes, Insurance, and HOA Fees Are the Monthly Catch-22
Your mortgage quote often lists principal and interest only. The lender will also require an escrow account for property taxes and homeowners insurance. Those two items together can easily add $500 to $800 a month on a moderate single-family home.
Take a $325,000 house in a suburb with a 1.1% effective tax rate. Annual property taxes are $3,575, or $298 a month. A homeowners policy in a wind-prone area can cost $2,400 a year, or $200 a month. A basic HOA fee is $75 a month. That is $573 a month above principal and interest before you buy a single sheet of drywall.
Get quotes for the exact house you want to buy. A tax estimate from the county assessor’s office is public information. Ask the seller for a copy of their current insurance statement and the last year’s HOA budget. Use those real numbers instead of a rule of thumb.
What the Lender Does Not Count
Your mortgage payment is not the only obligation in your life. Disability insurance, life insurance, health premiums, tuition, childcare, and retirement contributions do not show up in your debt-to-income ratio. If you fund a Roth IRA with $500 a month, that is a fixed expense in your real budget, but the bank ignores it. If you have a child in daycare at $1,100 a month, the lender sees no difference between you and a childless couple with the same salary.
Before you trust a pre-approval letter, subtract these non-debt obligations from your take-home pay. If your budget has no room for a birthday gift or a new pair of shoes, the house is too expensive.
A Better Way to Calculate Your Price Ceiling
Skip the pre-approval amount and try this with your actual bank statements.
- Write down your monthly take-home pay after taxes, insurance, retirement contributions, and automatic savings.
- Subtract fixed non-housing debts: student loans, car loans, personal loans, alimony, and child support.
- Subtract your average spending on food, utilities, transportation, phone, internet, clothing, and entertainment.
- The remainder is the maximum comfortable housing payment.
- From that, subtract expected property taxes, homeowners insurance, PMI, and HOA dues.
- The final figure is what you can pay toward principal and interest on a mortgage.
Now use a mortgage calculator in reverse. Let’s say your take-home pay is $4,700. Fixed debts are a $380 car payment and a $150 credit card minimum. Non-housing living costs are $1,700. That leaves $2,470. After $340 for property tax and $130 for insurance, the rest is $2,000 for principal and interest. At 6.5% on a 30-year loan, $2,000 supports about a $316,000 mortgage. With 10% down, your price ceiling is roughly $351,000. With 20% down, it is about $395,000.
Notice that this example uses no savings buffer. If you want a payment that will not make you anxious, reduce the mortgage amount by 10% and keep the difference in a high-yield savings account.
The Stress Test: What Happens When the Numbers Move
Rates are not static. Between 2021 and 2023, 30-year fixed rates went from the low threes to over seven percent. Every 1% increase in a $300,000 loan adds about $180 to the monthly payment. If you stretch to the top of the lender’s approval, a rate bump or an expiring rate lock can add $200 or more.
The same goes for insurance and taxes. Your effective property tax rate can rise with reassessment, and insurance premiums in storm-prone regions can jump 20% to 30% after one bad year. Ask the seller for actual tax and insurance bills, then add 10% to 15% to both as a stress test.
Your Affordability Number Is a Decision, Not a Formula
Lenders, real estate agents, and mortgage calculators all use inputs that do not include your tolerance for risk. If you are a teacher with a stable income and a nine-month emergency fund, you may feel fine at 35% of net pay. If your income depends on commission and two clients just left, you might want 20%. Neither answer is wrong if you can handle a $500 surprise every month without waking up at 3 a.m.
When I stopped focusing on the pre-approval and started focusing on the $210 I would have had left over, the decision became obvious. The house I chose cost about a quarter less than the maximum amount I was told to spend, and the room in my budget was far more comfortable than the extra square footage.
Run through the steps with actual numbers. Set your limit once, write it down, and do not let a mortgage calculator talk you out of what you already know about your own spending. The price tag might be lower than the lender’s cap. That only means the house you end up with will not be the one that strangles your future.