Buying a home is a big financial decision, and a clear affordability check helps. The 28/36 rule provides a simple framework to gauge how much home you can comfortably afford. This Home Affordability Calculator translates that rule into numbers you can act on, estimating loan size, monthly payments, and the price range that fits your budget. Input your income, debts, down payment, and loan terms to get started.
Home Affordability Calculator (28/36 Rule)
Introduction to affordability planning goes here. The 28/36 rule helps you separate housing costs from other debts, using two simple ratios: keep front-end housing costs (PITI) under 28% of gross income and total monthly debt payments under 36% of gross income. This calculator applies those guidelines to estimate a realistic price range, loan size, and monthly obligations so you can discuss options with confidence.
Introduction
The 28/36 rule is a practical yardstick many lenders use to gauge mortgage affordability. The rule splits the calculation into two parts. The front-end ratio focuses on housing costs, ensuring your PITI (principal, interest, taxes, and insurance) do not overwhelm your income. The back-end ratio looks at total monthly debt obligations, including every loan or payment you already owe. In combination, these ratios aim to keep home buying sustainable.
While this rule offers a sensible starting point, real-world affordability depends on many variables: local property taxes and insurance, down payment size, credit health, and future plans. The calculator on this page translates the two ratios into a concrete number you can use to shop confidently. It considers your income, existing debts, down payment, loan terms, and taxes and insurance to produce a realistic maximum loan amount and home price.
How to use the calculator above
To get the most accurate result, gather a few numbers before you start:
- Gross monthly income — include salary, bonuses, and any stable sources of monthly income.
- Existing monthly debts — car payments, student loans, minimum credit card payments, etc.
- Down payment — how much you can put toward the home upfront.
- Mortgage interest rate — use the rate you expect to secure or a reasonable market estimate (APR).
- Loan term — common choices are 15, 20, or 30 years.
- Property tax rate — local annual percentage of home value charged as tax.
- Estimated monthly homeowner’s insurance — a current estimate helps avoid surprises.
In the calculator, you’ll see three outputs. The maximum monthly PITI represents the cap on housing costs that align with the 28/36 rule. The maximum loan amount is an estimate of how much you could borrow given that cap, taxes, and insurance. The maximum home price is the resulting home price you could buy with that loan and your down payment. All figures are estimates and should be used as planning guides, not guarantees.
A worked example with specific numbers
Let’s walk through a concrete example to show how the numbers come together. Suppose you have:
- Gross monthly income (G): $6,400
- Existing monthly debts (D): $1,000
- Down payment: $60,000
- Mortgage APR: 6.5%
- Loan term: 30 years
- Property tax rate: 1.15% annually
- Estimated monthly insurance: $120
Step 1 — front-end cap (PITI): 0.28 × G = 0.28 × 6,400 = 1,792. Step 2 — back-end cap: 0.36 × G − D = 0.36 × 6,400 − 1,000 = 1,304. The calculator uses the smaller of these two values, ensuring both affordability tests are satisfied. So, Maximum monthly PITI = $1,304.
Step 3 — interest and term math: monthly rate i = 6.5% / 12 ≈ 0.0054167, number of payments n = 30 × 12 = 360. For the loan portion, the denominator for principal and interest is denom = i / (1 − (1 + i)^(−n)). With the numbers above, denom ≈ 0.00632. The combined denominator also includes the annual property tax rate term, giving denom_total ≈ 0.00727.
Step 4 — tax and insurance contributions to the loan amount: monthly tax on the home equals (tax_rate/100) × home_price / 12, but since we don’t yet know the price, we approximate tax impact using the down payment: taxTerm = (1.15% / 12) × $60,000 ≈ $57.50. Insurance is $120 per month. The numerator for the loan amount is M − taxTerm − insurance ≈ 1,304 − 57.50 − 120 ≈ 1,126.50.
Step 5 — solve for loan amount L: L ≈ 1,126.50 / (denom_total) ≈ $154,700. Step 6 — price up to you: Maximum home price ≈ L + down_payment ≈ $154,700 + $60,000 ≈ $214,700.
Takeaway: with these inputs, the calculator suggests you could comfortably borrow about $155k and buy a home around $215k when factoring in taxes and insurance. If you want to push the price higher, you’d need a larger down payment, lower debts, a higher income, a lower interest rate, or reductions in taxes and insurance. The numbers are sensitive to local costs, so it’s wise to run several scenarios.
Other genuinely helpful information
Understanding affordability isn’t just about math. Here are practical tips to apply the 28/36 rule in a real-world plan:
- Start with a budget baseline. List all monthly expenses, then add a conservative housing target. This helps prevent overcommitting when interest rates or taxes change.
- Consider a larger down payment. Increasing your down payment reduces the loan amount, which can dramatically affect both monthly payments and your qualifying price range.
- Shop for taxes and insurance. Property taxes vary by area, and homeowners insurance costs can differ by provider and coverage. A modest change can alter affordability noticeably.
- Account for future changes. If you expect income growth, a future-leaning plan can be more resilient. If you anticipate higher debt or new expenses, factor those into your scenario.
- Use the calculator for multiple scenarios. Try different down payment sizes, rates, or loan terms to see how your affordable price range shifts.
- Remember the limits. Lenders may require a bigger cushion for reserves, closing costs, and potential rate fluctuations. The numbers here are planning estimates, not guarantees.
- Consider mortgage programs. First-time buyer programs, down payment assistance, or rate locks can influence affordability and the total cost of ownership.
- Factor in HOA and maintenance. If you’re considering a condo or planned community, monthly HOA dues and ongoing maintenance should be included in your affordability test.
- Think about taxes strategically. If you itemize deductions, mortgage interest and property taxes might reduce your tax burden, affecting net affordability.
- Consult a lender. For a precise pre-approval, a lender can run your numbers with your credit profile and local rates to confirm what you can realistically borrow.
Related Calculators
Other calculators that solve closely related problems:
- Home Sale Profit Calculator
- Home Equity Loan Calculator Monthly Payments
- Home Equity Percentage Calculator
- Home Equity Loan Monthly Payment Calculator
- Home Equity Monthly Payment Calculator
- Home Loan Percentage Calculator
Frequently Asked Questions
What is the 28/36 rule, and why is it important?
The 28/36 rule is a practical guideline used by many lenders to gauge mortgage affordability. It recommends keeping housing costs (PITI) under 28% of gross monthly income and total debt payments under 36%. Following these limits helps ensure monthly housing costs stay manageable and that debt remains sustainable even if rates or other expenses change.
Does the calculator account for property taxes and homeowner’s insurance?
Yes. The calculator includes estimated property taxes and monthly insurance as part of the PITI calculation. Taxes depend on the home price and local tax rate, while insurance is a separate monthly amount you provide as input or estimate.
Can I adjust inputs if I plan to make a larger down payment later?
Absolutely. You can adjust the down payment input to see how a bigger upfront payment affects the maximum loan amount and home price. In many cases, a larger down payment increases your affordability and lowers monthly payments.
Why is the monthly payment shown as PITI?
PITI stands for principal, interest, taxes, and insurance. It represents the full monthly housing cost before other daily expenses, giving a clearer view of how much portion of your budget goes toward housing.
What if I have other monthly obligations, like student loans?
Other debts are included in the back-end ratio (the 36% cap). The calculator uses your existing monthly debts to determine the maximum allowable PITI so that your total debt payments stay within affordable bounds.
What happens if interest rates rise before I close?
Rising rates typically increase monthly payments for the same loan amount, which can reduce the affordable home price. It’s wise to run scenarios with higher rates to see how much price or down payment would be needed to stay within the same affordability bounds.
Why is this tool only an estimate?
Affordability depends on many real-world factors, including credit score, lender overlays, local taxes, insurance costs, HOA dues, and future income volatility. This calculator provides a realistic planning estimate, not a guaranteed loan offer.
What if my area has unusual taxes or HOA fees?
Local variations can impact affordability. Include property tax rate and any known HOA dues in the inputs when possible, and run multiple scenarios to gauge the range you should consider.
Does this tool replace talking to a lender?
No. It’s a planning aid to help you prepare and understand your options. A lender can offer a formal pre-approval, consider your full financial profile, and provide precise eligibility guidance.
How can I improve affordability quickly?
Improving affordability can come from increasing income, reducing existing debt, increasing the down payment, or securing a lower interest rate term. Even small changes can meaningfully raise the price range you can safely buy within the 28/36 framework.