House Affordability Calculator
Find out how much house you can afford based on income, debts and down payment.
A house affordability calculator estimates a purchase price by working backward from the monthly housing payment your income can reasonably support. This calculator uses annual gross income, monthly debt payments, down payment, interest rate, loan term, property tax rate, and annual insurance. It applies a simple underwriting-style limit where the maximum housing payment is the lower of 28% of gross monthly income or 36% of gross monthly income minus other monthly debts. That approach is often summarized as the 28/36 rule.
The result is useful because home shopping decisions are often made in terms of listing price, while lenders and budgets operate in terms of monthly payment. A home affordability calculator with down payment helps connect those views and reminds buyers that taxes, insurance, and existing debts can shrink the budget quickly.
How to use the House Affordability Calculator
- Enter "Annual gross income" before taxes, then add your recurring "Monthly debt payments". The calculator uses those two fields to apply the 28/36 rule to your monthly budget.
- Fill in "Down payment" with the cash you expect to put toward the purchase. A larger down payment can increase the affordable home price because it reduces the amount that must be financed.
- Set the expected "Interest rate" and "Loan term". These determine how much loan principal can fit inside the allowed principal-and-interest portion of the monthly budget.
- Add "Property tax rate" and "Insurance / year". Those ownership costs are included in the maximum housing payment, so higher estimates lower the home price the calculator can support.
- Read "Affordable home price" first, then compare the detail rows for "Loan amount", "Max monthly housing payment", "Principal & interest", and the tax and insurance lines.
Formula
Max payment = min(28% · income, 36% · income − debts)
Example: using a home affordability calculator with down payment
Suppose "Annual gross income" is $120,000, "Monthly debt payments" are $650, "Down payment" is $60,000, "Interest rate" is 6.25%, "Loan term" is 30 years, "Property tax rate" is 1.15%, and "Insurance / year" is $1,800. With those inputs, the calculator shows an "Affordable home price" of $424,345.
The monthly gross income is $10,000. Under the 28/36 rule, 28% of that is $2,800 and 36% minus the $650 of other debt is $2,950, so the tighter limit is $2,800. That becomes the calculator's "Max monthly housing payment". Using the entered rate and term, the tool backs into a purchase price where principal and interest are $2,243.34 per month, property tax is $406.66 per month, and insurance is $150.00 per month. Those pieces add to the $2,800 limit. The same result implies a "Loan amount" of $364,345 after subtracting the $60,000 down payment, and a "Down payment share" of 14.14%.
How to interpret the result
The result is best read as a planning ceiling, not a command to spend that amount. A how much house can I afford calculator can identify a supportable range, but comfort, savings goals, repair risk, and local costs still matter.
The 28/36 rule is a common guideline because it balances housing with other obligations. Even so, a household with high child-care costs, unstable income, or aggressive savings goals may want a stricter target.
If the affordable price feels lower than expected, taxes, insurance, debts, and rate are often the reason. Those variables affect affordability more than many buyers expect.
Next, you may also find these useful: Mortgage Calculator, Loan Calculator, Auto Loan Calculator.
Assumptions and limitations
- This calculator uses the 28/36 rule exactly as implemented in the code. It sets the maximum housing payment to the lower of 28% of gross monthly income or 36% of gross monthly income minus other monthly debts.
- Property taxes are estimated from the entered tax rate and the computed home price, while insurance is spread evenly across 12 months. Actual lender escrows, assessments, and premiums can differ.
- The calculation assumes a fixed-rate mortgage over the selected term. It does not include private mortgage insurance, HOA dues, utilities, maintenance reserves, or closing costs.
- Gross income is used instead of take-home pay because that is how many lending guidelines are framed. A household budget may still need a lower purchase target if net cash flow is tight.
Frequently asked questions
What is the 28/36 rule in a how much house can I afford calculator?
It is a common lending guideline. The idea is that housing costs should stay around 28% or less of gross monthly income, while total debt payments including housing should stay around 36% or less. This calculator uses the lower of those two limits.
Why does a home affordability calculator with down payment ask for other debts?
Because car loans, student loans, credit card minimums, and similar obligations reduce room left for housing. A salary that looks comfortable on paper can support far less home if recurring debts are high.
Does a larger down payment always increase affordability?
Usually yes, because it reduces the loan amount that must fit inside the monthly payment limit. It can also improve the borrowing profile in practice, although this calculator focuses on payment math rather than approval details.
Is the affordable home price the same as what a lender will approve?
Not necessarily. Lenders may use additional rules involving credit score, reserves, loan program, documentation, and mortgage insurance. The calculator is a planning tool, not a preapproval.
Why do property taxes and insurance matter so much?
They are part of the monthly housing payment in this model. In areas with high taxes or expensive insurance, those costs can consume hundreds of dollars per month, leaving less room for mortgage principal and interest.
Should I shop at the very top of the calculator's range?
Not automatically. Many buyers prefer to leave space for repairs, moving costs, emergencies, and future savings goals. Treat the result as a ceiling, not a target you must hit.
Sources and further reading
- Consumer Financial Protection Bureau: Debt-to-income ratio
- Consumer Financial Protection Bureau: Owning a home
- Consumer Financial Protection Bureau: Monthly mortgage payment costs
Last reviewed: 2026-10-02. See our editorial policy.
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Estimates only; not financial, tax or legal advice. Confirm figures with your lender or a licensed professional. Full disclaimer