One of the biggest mistakes home buyers make is starting their search before knowing what they can actually afford. They fall in love with a home, then discover the payments are $800/month more than their budget allows. Here's how to do it right.
The 28/36 Rule — Your Starting Point
Lenders use the 28/36 rule as a baseline for mortgage qualification. It works like this:
- 28% rule: Your total housing payment (principal, interest, property taxes, and homeowner's insurance — called PITI) should not exceed 28% of your gross monthly income.
- 36% rule: Your total monthly debt payments (mortgage + car loans + student loans + credit cards + any other debt) should not exceed 36% of your gross monthly income.
For example, if you earn $8,000/month gross, your maximum mortgage payment should be around $2,240 (28%), and your total debts including the mortgage should stay under $2,880 (36%).
Quick Calculation Table — Monthly Income to Max Mortgage
| Gross Monthly Income | Max Payment (28%) | Max Total Debt (36%) |
|---|---|---|
| $4,000 | $1,120 | $1,440 |
| $6,000 | $1,680 | $2,160 |
| $8,000 | $2,240 | $2,880 |
| $10,000 | $2,800 | $3,600 |
| $12,000 | $3,360 | $4,320 |
| $15,000 | $4,200 | $5,400 |
Step-by-Step: Calculate Your Home Buying Budget
Calculate your gross monthly income
Add up all income before taxes — salary, freelance, rental income, etc. Use your total household income if buying with a partner.
Multiply by 28% to get your max payment
This is your maximum PITI (Principal, Interest, Taxes, Insurance). Subtract your estimated monthly taxes and insurance to find your maximum P&I payment.
Check your existing debts
Add up all current monthly debt payments — car loans, student loans, credit card minimums. Subtract this from your 36% threshold to find what's left for a mortgage.
Use the lower of the two numbers
Take whichever limit is lower — the 28% housing limit or the remaining amount after the 36% total debt limit. That's your true maximum monthly payment.
Work backward to find your home price
Use our mortgage calculator to find what home price produces your maximum monthly payment at current interest rates.
Hidden Costs First-Time Buyers Miss
Your mortgage payment is just one part of the true cost of homeownership. Before setting your budget, make sure you account for:
Closing costs
2-5% of loan amount, typically $6,000-$15,000+
Maintenance & repairs
Budget 1-2% of home value annually ($4,000-$8,000 on a $400k home)
HOA fees
$200-$600/month in many communities
Utilities
Typically $200-$500/month more than renting an apartment
PMI
0.5-1.5% annually if down payment is under 20%
Landscaping/Snow removal
$1,000-$3,000/year depending on property and climate
The Impact of Interest Rates on Affordability
Interest rates dramatically affect how much home your budget can support. Consider a buyer with a $2,500/month maximum payment:
| Interest Rate | Max Loan (30yr) | With 20% Down |
|---|---|---|
| 5.0% | $466,000 | $582,000 |
| 6.0% | $417,000 | $521,000 |
| 6.9% | $379,000 | $474,000 |
| 7.5% | $357,000 | $446,000 |
| 8.0% | $341,000 | $426,000 |
A 1% difference in rate changes your maximum home price by roughly $45,000-$50,000. This is why improving your credit score before applying — and shopping multiple lenders — can make a significant difference in what you can afford.
How Much Should You Actually Spend?
Just because a lender approves you for a certain amount doesn't mean you should borrow that much. Lenders calculate maximum qualification — not optimal financial health. Many financial advisors suggest staying well below your maximum:
- Conservative: Keep housing at 20-25% of gross income for maximum financial flexibility and savings capacity.
- Moderate: 25-28% is comfortable for most buyers with stable income and limited other debt.
- Stretched: 28-33% works if you have exceptional job security, no other debts, and a solid emergency fund.
- Risky: Above 33% leaves little room for income disruption, emergency expenses, or retirement savings.
Ready to Calculate Your Exact Numbers?
Enter your home price, down payment, interest rate, and income into our mortgage calculator to see your exact payment, affordability rating, and full amortization schedule.
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