How to Use This Calculator
- 1
Enter Gross Monthly Income
Input your total income before taxes and deductions.
- 2
Specify Monthly Debts
Enter the total of all your recurring monthly debt payments (e.g., car loans, credit cards).
- 3
Input Annual Interest Rate
Enter the annual mortgage interest rate you expect to qualify for as a percentage.
- 4
Set Loan Term
Input the number of years you plan to repay the mortgage.
- 5
Provide Down Payment
Enter the upfront cash amount you plan to put toward the home purchase.
- 6
Estimate Monthly Property Taxes
Input your estimated monthly property tax amount for the home.
- 7
Estimate Monthly Home Insurance
Input your estimated monthly homeowners insurance premium.
- 8
Review your results
The calculator displays your maximum affordable home price, loan amount, monthly payment, DTI ratios, LTV, and total interest. The Affordability Insights panel shows your monthly budget split, remaining income after housing, and a breakdown bar of your monthly obligations.
Example Calculation
An individual earning $5,000/month with $500 in monthly debts and a $20,000 down payment wants to see what home price they can afford with a 4% interest rate over 30 years, plus $200/month for taxes and $100/month for insurance.
Gross Monthly Income ($)
5,000
Monthly Debts ($)
500
Annual Interest Rate (%)
4
Loan Term (years)
30
Down Payment ($)
20,000
Monthly Property Taxes ($)
200
Monthly Home Insurance ($)
100
Results
Max Home Price
$229,461
Max Loan Amount
$209,461
Monthly Payment
$1,000
Front-End Ratio
26.0%
Back-End DTI
36.0%
Tips
Reduce Debts to Boost Affordability
Lowering your existing monthly debt payments directly improves your back-end DTI ratio. Paying off a $300/month car loan, for example, could increase your max home price by roughly $60,000 at 4% interest over 30 years.
Increase Your Down Payment
A larger down payment reduces the loan amount, lowers your monthly payment, and can help you avoid PMI if you reach 20% equity. With the default example, increasing the down payment from $20,000 to $50,000 raises your max home price to $259,461.
Shop for Lower Rates
Even a 0.5% rate difference significantly impacts affordability. At 3.5% instead of 4%, the same $1,000/month payment supports a $222,694 loan vs $209,461 — a $13,000+ increase in buying power.
The Mortgage Affordability Calculator helps prospective homebuyers determine how much home they can realistically afford based on their income, debts, and financial profile.
It applies the standard 28/36 lender guidelines to calculate your maximum affordable home price, loan amount, monthly payment, and key DTI ratios.
For example, an individual with a $5,000 monthly income, $500 in debts, and a $20,000 down payment can afford a home up to $229,461 with a 4% interest rate over 30 years.
Navigating Debt-to-Income Ratios for Homeownership
Debt-to-income (DTI) ratios are fundamental metrics lenders use to assess your capacity to take on and repay a mortgage in 2026.
The "28/36 rule" is the most widely recognized benchmark: your front-end DTI (housing costs only) should ideally be no more than 28% of your gross monthly income, while your back-end DTI (all monthly debts, including housing) should not exceed 36%.
Some loan programs, like FHA loans, may allow for slightly higher ratios — up to 31% for the front-end and 43% for the back-end.
This calculator uses both limits and takes the more conservative result, ensuring you get a realistic affordability estimate that most lenders would approve.
Calculating Your Maximum Mortgage Affordability
This calculator determines your maximum affordable mortgage by first calculating the maximum monthly P&I payment you can afford based on both the front-end (28% of income minus taxes and insurance) and back-end (36% of income minus all debts, taxes, and insurance) limits.
It takes the lower of the two.
This affordable P&I payment is then fed into the standard loan amortization formula in reverse to determine the maximum loan principal that payment can support.
monthlyRate = annualInterestRate / 12 / 100
numPayments = loanTerm × 12
maxMortgagePayment = (grossMonthlyIncome × 0.28) - propertyTaxes - homeInsurance
maxDtiPayment = (grossMonthlyIncome × 0.36) - monthlyDebts - propertyTaxes - homeInsurance
affordablePI = min(maxMortgagePayment, maxDtiPayment)
maxLoanAmount = (affordablePI × ((1 + monthlyRate)^numPayments - 1)) / (monthlyRate × (1 + monthlyRate)^numPayments)
homePrice = maxLoanAmount + downPayment
Determining Affordability for a $5,000 Monthly Income
Let's assess the affordability for an individual with the following financial profile:
- Gross Monthly Income:
$5,000 - Monthly Debts:
$500 - Annual Interest Rate:
4% - Loan Term:
30 years - Down Payment:
$20,000 - Monthly Property Taxes:
$200 - Monthly Home Insurance:
$100
Step 1: Calculate Maximum Housing Payment (Front-End).
Max Housing PITI = $5,000 × 0.28 = $1,400Affordable P&I (Front-End) = $1,400 - $200 (Taxes) - $100 (Insurance) = $1,100Step 2: Calculate Maximum Total Debt Payment (Back-End).
Max Total Debt = $5,000 × 0.36 = $1,800Affordable P&I (Back-End) = $1,800 - $500 (Debts) - $200 (Taxes) - $100 (Insurance) = $1,000Step 3: Determine Actual Affordable P&I Payment.
Affordable P&I = min($1,100, $1,000) = $1,000Step 4: Calculate Max Loan Amount. Using the $1,000 P&I payment, a 4% rate, and 30-year term, the
Max Loan Amountis approximately $209,461.Step 5: Calculate Max Home Price.
Max Home Price = $209,461 (Loan) + $20,000 (Down Payment) = $229,461
This individual can afford a maximum home price of $229,461, with a monthly mortgage payment of $1,000 (P&I only).
The front-end DTI is 26.0% (under 28%) and the back-end DTI is 36.0% (at the 36% limit).
The Insights panel shows that after all housing obligations ($1,800/month), $3,200/month remains for other expenses.
Affordability Factors Beyond DTI and Income
While DTI ratios and income are crucial, true home affordability extends beyond these metrics.
Emergency savings are vital — experts recommend having 3-6 months of living expenses readily available.
Closing costs, typically 2-5% of the loan amount, are upfront expenses that can significantly impact your available cash.
For a $209,000 loan, this could mean an additional $4,200-$10,500.
Ongoing maintenance costs are also important, with a general rule of budgeting 1-4% of your home's value annually.
Finally, consider your future financial goals — aggressive mortgage payments might limit savings for retirement or children's education.
Frequently Asked Questions
How much mortgage can I afford?
Most lenders use the 28/36 rule: housing costs should not exceed 28% of gross monthly income, and total debt payments should stay under 36%. On a $75,000 salary, this means a maximum housing payment of about $1,750 per month including taxes and insurance.
What factors affect how much I can afford?
Key factors include your gross income, existing monthly debts, down payment amount, interest rate, property taxes, homeowners insurance, PMI, and HOA fees. Your credit score affects the rate you qualify for, which significantly impacts affordability.
Should I borrow the maximum I am approved for?
Financial experts generally advise against borrowing the maximum. Leave room for unexpected expenses, lifestyle costs, and savings goals. A mortgage that is 20-25% of your take-home pay (rather than 28% of gross) provides a more comfortable financial cushion.
How do property taxes and insurance affect affordability?
Property taxes (typically 0.5-2.5% of home value annually) and insurance ($1,000-$3,000+ per year) can add $300-$800 or more to your monthly payment. Always include these costs when determining what you can afford, as they reduce your available budget for the loan itself.