The Calculator Helper

Mortgage Affordability Calculator

Estimate how much you might borrow and the home price you could target.

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Estimated home price
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Estimated max loan
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Monthly payment budget
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Gross monthly income
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Deposit
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A rough estimate of principal and interest only — it excludes taxes, insurance and fees, and is not a mortgage offer or financial advice. Lenders assess more than these figures.

How affordability is estimated

Lenders typically limit your total debt payments to a share of your gross monthly income — the debt-to-income ratio. Subtracting your existing debts from that allowance leaves a budget for the mortgage payment.

budget = income ÷ 12 × DTI − existing debts

That monthly budget is then worked backwards through the standard loan formula, at your rate and term, to find the loan it supports. Adding your deposit gives an estimated home price. Because it ignores taxes and insurance, the real figure a lender uses is usually a little lower.

Worked example

On a $60,000 income with $300 of monthly debts, a 36% debt-to-income limit leaves about $1,500 a month for a mortgage. At 6% over 30 years that supports roughly a $250,000 loan, or about a $270,000 home with a $20,000 deposit.

Borrowing the max is rarely the goal

What you can borrow and what is comfortable to repay are different questions. The largest loan a lender allows can leave little room for emergencies, rate rises or life changes, so many people deliberately borrow below their ceiling.

Things that move the number

  • Rate and term. A higher rate or shorter term lowers the loan a given budget supports.
  • Existing debts. Clearing other commitments frees up monthly budget for a mortgage.
  • Hidden costs. Taxes, insurance and maintenance are real monthly money this estimate leaves out.

This is general information, not financial advice.

Frequently asked questions

What is debt-to-income (DTI)?
DTI is the share of your gross monthly income that goes to debt payments. Lenders often cap total debts at around 36% (sometimes higher), which sets a ceiling on the mortgage payment you can take on.
Does this include taxes and insurance?
No. It estimates principal and interest only. Property tax, insurance and any mortgage insurance reduce the loan amount a given budget supports, so treat this as an optimistic upper bound.
Why does my deposit change the home price but not the loan?
Your income and debts set how much you can borrow. The deposit is added on top of the loan to reach the home price, so a bigger deposit buys a more expensive home for the same monthly payment.
Will a lender offer exactly this?
Not necessarily. Lenders also weigh credit history, employment, other commitments and their own rules. This is a planning estimate, not a mortgage offer or financial advice.