House Affordability Calculator
House Affordability Calculator
Determining how much house you can afford is one of the most important steps in the home buying process. Buying a home is likely the largest financial commitment you will ever make, and going into it without a clear budget can lead to financial strain. The House Affordability Calculator helps you estimate a reasonable home purchase price based on your income, existing debts, down payment savings, and current mortgage interest rates.
Lenders use several guidelines to determine how much they are willing to lend you. The most common are the front-end ratio and the back-end ratio, also known as the housing expense ratio and the total debt-to-income ratio. The front-end ratio measures your projected monthly housing costs against your gross monthly income, while the back-end ratio measures all of your monthly debt obligations against your income.
The standard front-end ratio guideline is 28 percent, meaning your monthly housing costs should not exceed 28 percent of your gross monthly income. Monthly housing costs include mortgage principal and interest, property taxes, homeowners insurance, and any HOA dues or mortgage insurance premiums. The standard back-end ratio guideline is 36 percent, meaning your total monthly debt payments should not exceed 36 percent of your gross income.
These ratios are not absolute limits but guidelines. Some loan programs allow higher ratios, particularly FHA loans which may accept front-end ratios up to 31 percent and back-end ratios up to 43 percent. Beyond lender guidelines, you should also consider your personal financial situation. Financial experts recommend keeping total housing costs below 25 percent of your take-home pay for a comfortable margin.
Begin by entering your gross monthly income. Include salary, wages, bonuses, commissions, self-employment income, and any other reliable sources. Be conservative in your estimate, as overstating income can lead to unaffordable housing commitments.
Enter your existing monthly debt payments, including minimum credit card payments, car loans, student loans, and personal loans. Enter the down payment percentage you plan to make. A larger down payment reduces the loan amount and may eliminate PMI. Enter the expected interest rate and loan term. Check current rates from multiple lenders.
Press Calculate to see the maximum home price you can afford. For example, with $8,000 monthly income, $500 in debts, 10 percent down, 6.5 percent rate, and 30-year term, you could afford a home priced up to approximately $350,000.
The maximum monthly housing payment using the front-end ratio:
The maximum total debt payments using the back-end ratio:
The housing payment limit from the back-end ratio subtracts existing debts:
The loan amount is derived by inverting the amortization formula:
The maximum purchase price is: MaxPrice = LoanAmount / (1 - DownPaymentPercent).
Affordability estimates at 6.5 percent, 30-year term, 10 percent down:
| Monthly Income | Existing Debts | Max Home Price |
|---|---|---|
| $5,000 | $0 | $180,000 |
| $5,000 | $300 | $155,000 |
| $8,000 | $500 | $310,000 |
| $10,000 | $1,000 | $390,000 |
| $15,000 | $1,500 | $625,000 |
Keep a healthy margin below your maximum approved amount. Even if approved for $400,000, consider targeting $300,000 to $350,000 to allow room for maintenance, repairs, and other homeownership costs.
Remember to include one-time closing costs in your budget, typically 2 percent to 5 percent of the purchase price. Also maintain an emergency fund of 3 to 6 months of expenses after your down payment.
The 28/36 rule is a starting point. A conservative approach uses 25/33; an aggressive approach goes to 31/43 for borrowers with excellent credit and stable employment.
This calculator provides estimates based on standard underwriting guidelines. Actual loan approval depends on many factors not modeled here, including credit score, employment history, cash reserves, and the specific loan program.
The calculator does not include HOA fees, private mortgage insurance, or maintenance costs. Property taxes and insurance are estimates that may differ from actual costs. This tool is for educational purposes and does not constitute a loan pre-approval.
- What is the 28/36 rule and how does it affect my budget?
- Housing costs should not exceed 28% of gross monthly income, and total debt payments should not exceed 36%. The calculator uses these DTI ratios to estimate your price range.
- How much do I need for a down payment?
- Conventional loans allow as little as 3% down. FHA requires 3.5%. VA may require zero. 20% avoids PMI. The calculator lets you adjust down payment to see the impact.
- How does my credit score impact affordability?
- Score directly affects your interest rate. A 760+ score might get 1-2% lower rate than a 620 score, meaning tens of thousands in savings over the loan life.
- Does this calculator include property taxes and insurance?
- Yes. The calculator estimates PITI (Principal, Interest, Taxes, Insurance). You can adjust tax and insurance estimates to match your area.
- What DTI ratio do lenders actually approve?
- Most conventional lenders prefer front-end DTI of 28% or less and back-end of 36% or less. Some programs allow up to 50% with compensating factors.
- Consumer Financial Protection Bureau. "What is the 28/36 Rule?" consumerfinance.gov.
- Fannie Mae. "Selling Guide: Underwriting Analysis." fanniemae.com.
- Freddie Mac. "Homeownership Affordability." freddiemac.com.
- Bankrate. "How Much House Can I Afford?" bankrate.com.
- NerdWallet. "Home Affordability Calculator." nerdwallet.com.
Last updated: May 12, 2026