House Affordability Calculator

Work out the home price your income supports with the classic 28/36 debt-to-income rules, with PMI, taxes and savings constraints included.

The affordability math runs locally in your browser. Income and debt figures never leave your device.

Max home price
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Max loan
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True monthly
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DTI at that price
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PMI is modelled at 0.5% of the loan per year when the down payment is under 20% — real rates vary with credit score and loan-to-value.

Affordability bands (DTI ceilings)
Conservative
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28 / 36 %
Moderate
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31 / 43 %
Aggressive
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40 / 50 %
Assumptions

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Want the payment schedule for a specific price? Try the mortgage calculator.

Estimates based on standard underwriting rules of thumb — not a pre-approval and not financial advice; your lender’s criteria govern.

How It Works

The calculator asks the same question a lender does — what monthly housing payment can your income support? — and inverts the mortgage-payment formula to find the loan behind it. With a monthly rate i = annual rate ÷ 12 and n = term × 12 months, a loan L costs L × i(1+i)ⁿ ÷ ((1+i)ⁿ − 1) per month (interest and principal). Setting that payment equal to your housing budget gives the maximum loan, and maximum price = loan ÷ (1 − down payment %). Worked example at defaults — $85,000 gross yearly income, $500/mo debts, 10% down, 6.5% for 30 years, no taxes/HOA entered: monthly income $7,083, the 28% front-end rule allows $1,983 of housing, and after subtracting $0 extras the loan that fits is about $294,000, i.e. a $327,000 home — before checking whether your down-payment savings can actually cover that purchase.

DTI: 28/36, and which rule binds
Front-end DTI is housing costs (principal, interest, taxes, insurance, HOA, PMI) as a share of gross monthly income; the classic discipline is 28%. Back-end DTI adds all other minimum debt payments and is held to 36%. Both ceilings produce a maximum loan — the smaller one binds, and the card tells you which. High debts shrink the back-end budget fast; taxes, insurance and HOA are subtracted from both.
Why payment ≠ price
The mortgage payment is only part of owning: escrowed property tax and homeowners insurance, HOA dues, and (if you put down less than 20%) private mortgage insurance all ride on top. This tool adds them into the true monthly figure, so compare the true monthly — not the loan payment — against what you actually want to spend each month. Closing costs (estimated at 2–5% of price) must also fit inside your savings, which is checked against the down-payment amount you enter.
The 20% equity and PMI logic
With less than 20% down, US conventional lenders typically charge PMI — modelled here at 0.5% of the loan balance per year, divided by twelve, a common mid-market assumption (real rates run roughly 0.2–2% depending on credit and LTV). Because PMI is a housing cost, it eats into the DTI budget and lowers the affordable price further; the slider assumes PMI applies for any down payment below 20%.

Frequently Asked Questions

I’m self-employed — will a lender agree with this number?

Maybe not. Underwriters average self-employment income over two years of tax returns and subtract write-offs, so your qualifying income can be lower than what you actually earn. Lenders also scrutinise reserves and seasonality. Treat this calculator as your personal planning number; expect the formal qualifying number to be more conservative.

My bank pre-qualified me for more. Which number should I trust?

Trust both for what they are: a pre-approval is a ceiling on what the underwriter may lend at today’s rates and your stated debts, not a recommendation. This tool shows what standard 28/36 debt-to-income discipline supports. A larger approved amount means a larger payment forever — many buyers who stretched to the pre-approval limit later describe being house-poor.

What if rates move before I buy?

Affordability swings hard with the rate: on a 30-year loan, each extra full percentage point of interest reduces the loan that fits the same monthly payment by roughly 9–10%. Re-run the calculator whenever rates move, and remember the DTI rules apply to the rate you actually lock, not today’s quote.

When does the PMI go away?

With private mortgage insurance you can usually request removal once your equity reaches 20% by amortisation plus appreciation, and it terminates automatically at 22% based on the original schedule (rules for US conventional loans; FHA’s MIP works differently and often lasts the whole loan). Keeping this tool’s down-payment slider at 20% or above simply removes the PMI line.

Is anything uploaded to a server?

No. Your income, debts and results are processed locally in your browser with plain JavaScript and never transmitted anywhere. No account, no tracking, no network request attached to the calculation.