House Affordability Calculator
Find out how much house you can afford based on your income.
- Author
- CentCompass
- Last Updated
- Reading Time
- 4 min read
Affordable home price
$321,640.96
Loan amount
$281,640.96
Max monthly payment (PITI)
$2,200.00
Principal & interest
$1,780.16
Property tax
$294.84
Home insurance
$125.00
Based on a 36% debt-to-income (DTI) guideline; the monthly budget covers principal, interest, property tax, and insurance (PITI). Estimate only — lenders use additional factors.
What is the House Affordability Calculator?
A house affordability calculator estimates the home price your finances can support, working backwards from your income, existing debts, down payment, and a lender's debt-to-income guideline. It answers a different question from a mortgage calculator: instead of telling you what a given house costs, it tells you which houses are realistically within reach before you start viewing them.
How the calculation works
The calculator applies a debt-to-income (DTI) limit of 36% to your gross monthly income, then subtracts your existing monthly debt payments. What remains is the budget available for housing. Because that budget must cover principal, interest, property tax, and insurance together, the calculator strips out the estimated monthly tax and insurance first, leaving the amount available for principal and interest. It then reverses the amortization formula to find the largest loan that payment supports, and adds your down payment to arrive at a home price.
The formula
Maximum housing payment = (gross monthly income × 0.36) − existing monthly debts. Subtracting monthly tax and insurance from that figure gives the principal-and-interest budget, M. The loan is then recovered by inverting the amortization formula: P = M · [(1+r)^n − 1] / [r(1+r)^n], where r is the monthly rate and n the number of payments. Affordable home price = P + down payment. Every input moves the result: lower debts or a bigger down payment raise the ceiling, while a higher rate lowers it.
Worked example
With $90,000 of gross income, $500 in monthly debt payments, and $40,000 saved for a down payment, gross monthly income is $7,500. At a 36% DTI the total debt budget is $2,700; removing the $500 of existing payments leaves about $2,200 a month for full housing costs. Once estimated property tax and insurance are carved out, the remainder supports the loan, and adding the $40,000 down payment gives the affordable price. Note how paying off a $500 car loan would lift the housing budget from $2,200 to $2,700 — a substantial jump in buying power.
Tips
- Clearing a car loan or credit card frees its full payment for housing and can move your ceiling sharply.
- A larger down payment raises the price ceiling and removes PMI at 20%.
- Lenders weigh credit score, reserves, and job history alongside DTI, so approval is never purely arithmetic.
- Get pre-approved before viewing homes — sellers treat pre-approved offers very differently.
- The maximum you qualify for is not the amount you should spend; leave room for maintenance and savings.
Common mistakes
- Treating the maximum approved amount as a target rather than an outer limit.
- Forgetting HOA dues, which lenders count against the same budget as PITI.
- Budgeting only the down payment and being caught out by closing costs of 2–5% of the price.
- Using gross income intuitively while forgetting that taxes and retirement contributions come out first.
- Assuming a pre-approval is final — it is conditional and can change if your debts or rates move.
Limitations
This model uses a single 36% back-end DTI rule, but real underwriting varies by loan program: FHA, VA, and USDA loans apply different ratios and allow different compensating factors. It relies on the tax and insurance figures you supply rather than local data, does not model HOA dues, PMI, or credit-score-driven rate differences, and produces an estimate rather than a pre-approval.
Frequently asked questions
What is debt-to-income (DTI)?
DTI is the share of your gross monthly income consumed by debt payments. Lenders look at a front-end ratio covering housing alone and a back-end ratio covering all debts, commonly capping the back-end figure somewhere between 36% and 43%.
What is the 28/36 rule?
It is a long-standing guideline suggesting housing costs stay under 28% of gross income and total debt payments under 36%. This calculator applies the 36% back-end figure, which is the binding constraint for most buyers who carry any other debt.
Does the budget include taxes and insurance?
Yes. The model works in PITI terms, so property tax and homeowners insurance are removed from the housing budget before the loan is calculated. Ignoring them would overstate affordability by a wide margin in high-tax counties.
How much down payment do I need?
It depends on the program. Conventional loans can go well below 20%, FHA lower still, and VA loans may require nothing down for eligible borrowers. More money down raises your price ceiling, removes PMI at 20%, and reduces lifetime interest.
Is this a loan pre-approval?
No. This is an estimate based on the figures you enter. A pre-approval involves a lender verifying your income, assets, debts, and credit, and only that process produces a number you can rely on when making an offer.
How much house can I afford on a given salary?
Divide the salary by twelve, take 36% of that, subtract your existing monthly debt payments, and the remainder is your all-in housing budget. How much home that buys then depends heavily on the interest rate, your down payment, and local tax rates.
How do interest rates change what I can afford?
Rates move affordability more than almost any other variable. Because the payment is fixed by your budget, a higher rate means a smaller loan supports the same payment — a couple of percentage points can shift your price ceiling by tens of thousands of dollars.
What cash do I need beyond the down payment?
Closing costs typically run 2–5% of the purchase price, prepaid escrow items add several months of tax and insurance, and lenders like to see reserves left over afterwards. Budgeting the down payment alone is the most common cash-flow surprise for first-time buyers.
Does my credit score affect affordability?
Indirectly but significantly. Credit score does not change the DTI arithmetic, but it drives the interest rate you are offered and the cost of PMI, and both feed straight back into how much loan a given payment supports.
What if I am self-employed?
Lenders generally average two years of documented net income rather than gross receipts, which often produces a lower qualifying figure than self-employed borrowers expect. Speak to a lender early so you know which income number they will actually use.
Related calculators
Related guides
Sources
- CFPB — Understand the different kinds of loans available
- FHFA — Conforming Loan Limit Values
- Freddie Mac — Primary Mortgage Market Survey
How this page is produced
Editorial process. CentCompass is maintained independently, and this page is written and checked against the official publications listed above before it goes live. There is no separate editorial reviewer. This page was last checked on . See our editorial policy.
How the calculations work. Every result comes from a small, unit-tested calculation engine rather than a spreadsheet or a hardcoded table. Loans use the standard amortization formula, growth uses compound-interest math, income tax applies the federal progressive brackets, and payroll applies Social Security and Medicare rules. Our methodology sets out each one.
Where the figures come from. Tax brackets, standard deductions, FICA parameters, and contribution limits are stored once in a dated registry and read directly by the calculators — the same values appear in the text above, so the two can never drift apart. Each figure records its source, effective tax year, and review status on our data sources page.
Update policy. Regulatory figures are checked against their primary source when the IRS, SSA, or another authority publishes new values — typically each autumn for the following tax year — and again at the scheduled review date recorded for each dataset. Figures that have not been checked yet are marked as draft on the data sources page until that check is complete.
Educational purposes only — not financial, tax, or investment advice (disclaimer).