Mortgages

Mortgage Affordability Calculator

Calculate the maximum home price and mortgage loan you can afford based on your gross income, down payment, monthly debts, and interest rates.

What this calculator does

The Mortgage Affordability Calculator estimates your result instantly from the values you enter, using standard mortgages formulas. Calculate the maximum home price and mortgage loan you can afford based on your gross income, down payment, monthly debts, and interest rates. Calculations run in your browser, so nothing you type is sent to a server, and the output is an estimate for planning rather than financial advice.

About Mortgage Affordability Calculator

The Mortgage Affordability Calculator helps prospective homebuyers determine their maximum home purchasing power based on standard 28/36 underwriting guidelines, income, debts, and down payment.

Formula & Mathematical Calculation

Max Front-End Monthly Housing = Gross Monthly Income × 0.28

Max Back-End Total Obligations = Gross Monthly Income × 0.36

Max Loan Amount = Allowable P&I × [ (1 + r)^n - 1 ] / [ r(1 + r)^n ]

Calculation Example

Example: $10,000/mo income, $600/mo debts, $60k down payment @ 6.5% interest → Max Home Price = $415,972 ($355,972 loan + $60k down).

Key Benefits

  • Calculates maximum home purchase price based on lender underwriting rules
  • Accounts for property taxes, homeowners insurance, and HOA dues
  • Evaluates impact of existing monthly debts on borrowing capacity
  • Provides conservative vs. aggressive purchasing power scenarios
  • Helps buyers secure pre-approval with realistic budgets

How to Use this Calculator

  1. Enter Gross Household Income
    Input total pre-tax monthly or annual income.
  2. Input Available Down Payment
    Enter cash savings allocated for down payment.
  3. List Monthly Debt Obligations
    Enter monthly recurring payments for credit cards, car loans, and student loans.
  4. Set Interest Rate and Loan Term
    Enter mortgage interest rate and loan term (15 or 30 years).
  5. View Purchasing Power
    Click Calculate to view recommended and maximum affordable home prices.

Assumptions & Limitations

What the calculation assumes

  • Every value you enter is treated as an exact, known amount.
  • Rates and contributions are assumed to stay constant for the whole period unless the form asks for them separately.
  • Results use standard financial formulas and ignore fees, penalties and promotional terms that are not entered above.
  • Inflation, tax changes and market volatility are not modelled unless a field for them is provided.
  • Amounts are unit-agnostic: results are returned in the same currency you enter.

What it does not cover

  • Mortgage Affordability Calculator produces estimates for education and planning, not a quote, offer or professional advice.
  • Real-world outcomes differ when fees, taxes, rounding rules or provider-specific terms apply.
  • Local regulations and tax rules vary by country and change over time; verify current rules for your jurisdiction.
  • Figures are only as accurate as the inputs you supply — check them before acting on the result.
  • For decisions with lasting financial impact, confirm the numbers with a qualified professional.

Frequently Asked Questions

The front-end rule states monthly housing expenses (PITI) should not exceed 28% of gross monthly income. The back-end rule states total monthly debt obligations (housing + car loans + credit cards + student debt) should not exceed 36%.

Lenders qualify you based on total monthly housing payment, not just the loan principal. High local property taxes, home insurance, or steep HOA fees consume available monthly debt allowance, reducing the maximum mortgage amount you can borrow.

As a rule of thumb, every 1% increase in mortgage interest rates reduces a buyer's purchasing power by roughly 10%. A monthly payment that supports a $400,000 loan at 5% supports only about $360,000 at 6%.

Lenders calculate max loan limits based on gross income without considering personal lifestyle expenses (childcare, groceries, retirement savings, travel). Borrowing your full approved maximum often leaves you 'house poor'.

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Next step: browse the full Mortgages calculators or read the related guides for context before you decide.