The short answer: an affordability estimate starts from budget assumptions, not lender approval. It uses income, monthly debts, down payment, interest rate, term and housing-cost assumptions to estimate a home price and mortgage amount that may fit the values entered.
Use the home affordability calculator when you are starting from a budget. If you already know the loan amount, use the mortgage payment calculator instead.
Inputs that change the estimate
The live affordability calculator uses these inputs:
- Annual gross household income
- Monthly debt payments
- Down payment
- Fixed annual interest rate
- Loan term
- Property taxes per year
- Homeowners insurance per year
- HOA fees per month
- PMI per month
- Editable planning guidelines for housing expense and total debt
Changing any of these inputs can change the result. A higher down payment can raise the estimated home price. Higher property taxes, insurance, HOA or PMI reduce the monthly room available for principal and interest.
Gross income and monthly debt
Gross income means income before taxes and deductions. Monthly debts are recurring obligations such as auto loans, student loans, credit card minimum payments and personal loans. The CFPB describes debt-to-income ratio as monthly debt payments divided by gross monthly income.
This site’s calculator uses the monthly debt field to reduce the total-debt budget. It does not decide whether a lender will accept a debt-to-income ratio.
Worked example
Using the calculator’s tested example values:
| Input or result | Value |
|---|---|
| Annual gross income | $120,000.00 |
| Monthly debts | $500.00 |
| Down payment | $50,000.00 |
| Interest rate and term | 6.50 percent for 30 years |
| Monthly non-principal costs | $600.00 |
| Maximum monthly housing payment | $2,800.00 |
| Principal-and-interest budget | $2,200.00 |
| Estimated loan amount | $348,063.80 |
| Estimated home price | $398,063.80 |
In this example, the housing expense guideline is the limiting assumption. A different tax, insurance, HOA, PMI, rate or term can produce a different estimate.
How to interpret guideline percentages
The calculator’s default planning guidelines are 28 percent for housing expense and 36 percent for total debt. These are planning controls you can adjust, not universal underwriting rules.
Actual affordability depends on more than a calculator. The CFPB encourages looking at income, expenses, savings priorities and other homeownership costs before choosing a target payment.
Why this is not preapproval
Preapproval requires lender review of credit, income, assets, debts, documentation, loan program rules and property details. This guide and calculator do not access that information and do not determine eligibility.
Treat the result as a planning range. Then compare it with your own monthly comfort level and lender documentation.
Sources and methodology
Examples on this page use this site's tested mortgage utilities. External sources support consumer-protection context and terminology; they do not replace lender documentation.
Planning disclaimer
This guide and its examples are for education and planning only. They are not mortgage approval, preapproval, a rate quote, tax advice, or lender advice.