The internet is full of mortgage calculators that tell you how much you can borrow. What they don’t tell you is how much you should borrow. Those two numbers are often wildly different, and confusing them is how people end up house-poor: technically homeowners who can’t afford to do anything else because every spare dollar goes to housing costs.
The 28/36 Rule as a Starting Point
The traditional guideline says your monthly housing costs shouldn’t exceed 28% of your gross monthly income, and your total debt payments shouldn’t exceed 36%. If you earn $8,000 per month before taxes, that means housing costs up to $2,240 and total debt payments up to $2,880.
Housing costs in this calculation include principal and interest on the mortgage, property taxes, homeowners insurance, private mortgage insurance (PMI) if applicable, and HOA dues. It doesn’t include utilities, maintenance, or repairs, which add another $500 to $1,000 per month for a typical home.
The 28/36 rule is conservative. Many lenders approve borrowers up to 43% DTI or higher. But conservative isn’t bad. It leaves room for the unexpected expenses that homeownership inevitably brings.
Working Backward From Your Budget
Instead of starting with a home price and seeing if you can afford it, start with your monthly budget and work backward to find the right price.
List your actual monthly take-home pay. Not gross income, but the amount that actually hits your bank account. Subtract all non-housing expenses: food, transportation, insurance, debt payments, savings, entertainment, and a cushion for irregular expenses. What’s left is what you can put toward total housing costs.
If your take-home is $6,000 and your non-housing expenses are $3,500, you have $2,500 available for housing. Subtract estimated property taxes ($300/month), insurance ($150/month), and maintenance reserves ($200/month). That leaves about $1,850 for principal and interest.
At 6.5% interest on a 30-year mortgage, $1,850 per month supports a loan of approximately $292,000. Add your down payment to find the maximum purchase price. With $30,000 down, your maximum is about $322,000.
The Down Payment Reality
The 20% down payment is a benchmark, not a requirement. On a $350,000 home, 20% down is $70,000. Most first-time buyers don’t have $70,000 in cash.
Lower down payment options exist. Conventional loans allow as little as 3% down ($10,500 on a $350,000 home). FHA loans require 3.5% down. VA loans and USDA loans offer 0% down for eligible borrowers.
The tradeoff for lower down payments is private mortgage insurance (PMI), which costs 0.5% to 1.5% of the loan amount annually. On a $340,000 loan (5% down on $350,000), PMI might add $140 to $425 per month to your payment. PMI drops off once you reach 20% equity.
A larger down payment also means a smaller loan, lower monthly payments, less total interest paid, and more equity from day one. If you can put 10% to 15% down without emptying your emergency fund, you strike a reasonable balance.
Property Taxes: The Variable Nobody Mentions
Property taxes vary enormously by location. New Jersey’s average effective property tax rate is about 2.2%, meaning a $350,000 home costs $7,700 per year in taxes. Texas averages about 1.7% ($5,950 per year). Hawaii averages 0.3% ($1,050 per year).
On a monthly basis, property taxes in high-tax states add $500 to $700 to your housing cost. This isn’t a small number. Two identical homes at the same purchase price in different states can have monthly payments that differ by $500 or more solely because of property taxes.
Research the specific tax rate for the municipality and county where you’re buying. County assessor websites show current tax bills for any property. Don’t assume the seller’s tax bill will be yours. Reassessment at sale often adjusts the property value, and your tax bill changes accordingly.
The Hidden Costs That Blow Budgets
First-year homeownership costs beyond the mortgage regularly surprise people:
- Immediate repairs and upgrades: The house you bought needs things fixed. Paint, minor repairs, appliance replacements. Budget $2,000 to $5,000 for the first year.
- Furniture and furnishing: A bigger space needs more furniture. Moving from a one-bedroom apartment to a three-bedroom house might require $3,000 to $10,000 in furniture.
- Landscaping and exterior: Lawn equipment, garden supplies, tree trimming. These costs don’t exist when you rent.
- Utility increases: Heating and cooling a larger space costs more. A 2,000 sq ft house costs roughly twice what a 1,000 sq ft apartment costs for utilities.
The Stress Test
Before committing to a mortgage amount, stress test your budget against three scenarios:
Job loss: If you lost your income for three months, could you still make the mortgage payment from savings? Six months? If not, you’re too stretched.
Interest rate increase: If you’re considering an ARM, can you handle the payment at the maximum rate the loan allows? If a 2% rate increase would break your budget, a fixed-rate mortgage is the safer choice.
Major repair: If the furnace died ($4,000 to $8,000 to replace) or the roof needed work ($8,000 to $15,000), could you handle it without going into debt? Homeownership means these costs are yours, not a landlord’s.
If any of these scenarios would cause financial crisis, the house is too expensive regardless of what a lender approves.
When Renting Makes More Financial Sense
Buying isn’t always better than renting. In high-cost areas where home prices are 20x to 30x annual rent, renting and investing the difference often builds more wealth than buying. The New York Times rent-vs-buy calculator can model this for your specific situation.
Buying makes less sense when you might move within three to five years. Closing costs, agent commissions, and the early years of mortgage amortization (where payments are mostly interest) mean you need at least five years to break even compared to renting in most markets.
Don’t buy a house because you think you should or because someone told you renting is “throwing money away.” Rent pays for shelter, flexibility, and freedom from maintenance costs. Those are real benefits with real value.
The Right Number for You
The right home price is the one that lets you make the mortgage payment, build an emergency fund, save for retirement, enjoy your life outside of housing costs, and sleep well at night knowing you can handle setbacks.
If a home at your maximum approved amount prevents any of those things, buy less house. A smaller home or a less trendy neighborhood that keeps your housing costs comfortable is a better financial decision than the dream home that keeps you up at night worrying about money.