Home Affordability Calculator
Find out how much house you can afford. This home affordability calculator turns your income, debts and down payment into a realistic maximum home price.
What it does
The Home Affordability Calculator estimates the largest home price you can realistically support, based on your income, existing debt payments, down payment, and a maximum debt-to-income ratio. It turns your budget into a target price so you can house-hunt with confidence.
Data sources & parameters
This calculator uses standard financial formulas and runs entirely in your browser. It needs no external rate data — your result is computed only from the values you enter above.
We always strive to use the latest data for every variable so our results and reports are as accurate as possible. Even so, errors are possible — you should not rely on this tool or its report alone, and we accept no liability for any decision made based on it.
The formula
max_payment = income/12 × DTI − debts; max_loan = max_payment × (1 − (1 + i)^(−n)) / i; max_price = max_loan + down_payment, where i is the monthly rate and n the number of months
How it works
It first works out the monthly mortgage payment your income can carry after existing debts, using your debt-to-income limit. That affordable payment is then converted into a maximum loan with a standard amortisation formula, and your down payment is added to give the top home price.
Where it is used
- Setting a realistic price ceiling before you start viewing homes
- Seeing how a bigger down payment or lower debts lifts your budget
- Testing how interest rates change the price you can afford
Worked example
A buyer earning $100,000.00 a year with $500.00 of monthly debts and a $50,000.00 down payment, capped at a 36% debt-to-income ratio, can support … a month. Over a 30-year loan at 6%, that funds a loan of … and a maximum home price of ….
What the home affordability calculator does
The home affordability calculator estimates how much house you can afford, so you do not fall for a listing that turns out to be beyond reach. It works from your gross annual income, your existing monthly debt payments, the down payment you have saved, the mortgage interest rate, the loan term, and a maximum debt-to-income ratio.
The result is the highest price you could pay while keeping your total debt within a sensible share of your income, a ceiling you can use to filter listings from the start.
How affordability is calculated
The calculation follows the same logic a lender uses, in three steps.
First, it multiplies your gross monthly income by your maximum debt-to-income ratio. The product is the most you should spend on all debt combined.
Second, it subtracts the debts you already have. Car loans, student loans, credit card minimums and other commitments compete with the mortgage for the same share of income. What remains is the monthly mortgage payment you can afford.
Third, a standard amortisation formula converts that payment, at your interest rate and loan term, into the largest loan whose repayments match it. Your down payment is added on top, because it funds part of the purchase directly. The sum of the loan and the down payment is your maximum home price.
The inputs that move your budget
- Income lifts the whole calculation, because the affordable payment is a share of what you earn. It is the biggest driver of how much you can borrow.
- Every monthly debt payment you already owe reduces the mortgage payment you can afford, and so the price you can reach. Clearing a debt before you buy can raise your ceiling noticeably.
- The down payment adds directly to the price you can afford and reduces the loan you need.
- A lower interest rate means each payment repays more principal, so the same budget supports a larger loan. Small changes in the rate can move your maximum price more than buyers expect.
The debt-to-income ratio
The debt-to-income ratio caps total debt at a share of income that leaves enough for everyday living, saving and the unexpected. A stricter ratio produces a more conservative price and a bigger safety margin; a looser one allows a higher price but tighter monthly finances.
Lending rules differ by country and by lender, and your own comfort with risk matters too, so treat the default as a starting point. Lower the ratio for a cautious plan. If a lender in your market allows more and your income is stable, you might raise it, though borrowing to the maximum leaves little cushion.
How to use the calculator
- Enter your gross annual income before tax.
- Enter your total existing monthly debt payments.
- Enter the down payment you have available.
- Enter the mortgage interest rate you expect.
- Enter the loan term in years.
- Set the maximum debt-to-income ratio you want to apply.
The calculator shows your affordable monthly payment, the maximum loan that payment supports, and the maximum home price once your down payment is included.
Reading the results
The maximum home price is a ceiling, not a target. Buying at the top of your range leaves little room for rising rates, maintenance, insurance, property taxes and the ordinary surprises of owning a home, so many buyers shop below their maximum to keep the monthly budget comfortable.
Test a few scenarios. Raise the interest rate to see how a less favourable market would affect you, since rates can change before you sign. Lower your debts to see the effect of paying them down first, and increase the down payment to see how extra saving lifts your reach.
Knowing your maximum before you start viewing saves time on homes you cannot support and prepares you for the conversation with a lender. Revisit the numbers whenever your income, savings or the interest rate changes.
This article is general information only and is not financial advice.
About This Home Affordability Calculator
Use this home affordability calculator to get an instant estimate based on the figures you enter. Adjust the inputs above to match your situation, or browse all our calculators to plan your next step.
Frequently asked questions
How does the home affordability calculator work?
What is a debt-to-income ratio?
Does a bigger down payment let me buy a more expensive home?
Why does the interest rate change how much I can afford?
Is this the same as a mortgage pre-approval?
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