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February 12, 20265 min read

How Much House Can I Afford?

The answer depends on more than just your income. Here's how lenders calculate affordability — and how to think about it yourself.

"How much house can I afford?" is one of the first questions every homebuyer asks. The answer depends on several factors: your income, debts, down payment, credit score, and the current interest rate environment. Here's how to think about it.

The Lender's Perspective: DTI Ratios

Lenders use debt-to-income (DTI) ratios to determine how much you can borrow. There are two DTI ratios:

Front-end DTI (Housing Ratio): Your proposed housing payment (PITI — principal, interest, taxes, insurance) divided by your gross monthly income. Most lenders want this below 28–31%.

Back-end DTI (Total DTI): All monthly debt payments (housing + car loans + student loans + credit cards + other) divided by gross monthly income. Most conventional loans allow up to 45%; FHA allows up to 57% in some cases.

Example:

  • Gross monthly income: $8,000
  • Maximum housing payment (31%): $2,480
  • Maximum total debt (45%): $3,600
  • Existing monthly debts (car + student loans): $800
  • Maximum housing payment after existing debts: $2,800

    • In this example, the housing ratio is the binding constraint at $2,480/month.

    The 28/36 Rule

    A traditional rule of thumb is the 28/36 rule:

  • Spend no more than 28% of gross income on housing
  • Spend no more than 36% on total debt

    • This is more conservative than what lenders allow, but it's a reasonable guideline for financial health.

    What $2,500/Month Buys in NJ

    At a 7% interest rate on a 30-year loan:

  • $2,500/month in P&I supports approximately a $376,000 loan
  • Add property taxes ($500–$700/month in NJ) and insurance ($150/month)
  • Total housing payment: $3,150–$3,350/month

    • This means a $2,500 P&I payment in New Jersey actually requires a gross income of approximately $10,000–$12,000/month to stay within the 28–31% front-end ratio.

    The Down Payment Factor

    Your down payment affects both your loan amount and your monthly payment:

  • **3% down on $400,000:** $12,000 down, $388,000 loan, ~$2,581/month P&I
  • **10% down on $400,000:** $40,000 down, $360,000 loan, ~$2,395/month P&I
  • **20% down on $400,000:** $80,000 down, $320,000 loan, ~$2,129/month P&I (no PMI)

    • A larger down payment reduces your monthly payment and eliminates PMI, but requires more upfront capital.

    Don't Forget the True Cost of Homeownership

    Lenders calculate affordability based on PITI, but the true cost of homeownership includes:

  • **Maintenance and repairs:** Budget 1–2% of home value annually
  • **HOA fees:** If applicable
  • **Utilities:** Often higher than renting
  • **Lawn care, snow removal, etc.**

    • A home that's "affordable" by lender standards may be a stretch when you factor in all costs.

    The Emotional vs. Financial Decision

    Lenders will tell you the maximum you can borrow. That's not necessarily what you should borrow. Consider:

  • How stable is your income?
  • Do you have an emergency fund?
  • Are you planning major life changes (kids, career change)?
  • What are your other financial goals?

    • Many financial advisors recommend being conservative — borrowing less than the maximum to maintain financial flexibility.

    Get Pre-Approved for a Real Number

    The best way to know exactly what you can afford is to get pre-approved. We'll review your income, debts, and credit, and give you a firm number based on your actual financial situation — not a generic calculator.