Mortgage Affordability Calculator
Mortgage Affordability Calculator is a free finance tool that runs directly in your browser with no account required.
About this tool
Instead of starting from a home price, this calculator starts from your income and works backward: given your debts, down payment, interest rate, property tax, and insurance, it solves for the largest home price that keeps your total debt-to-income ratio at your chosen limit. It also shows Conservative (36%), Standard (43%), and Stretch (50%) DTI scenarios and estimates your cash to close, all downloadable as CSV.
How to use
- Enter your Annual income and current Monthly debt payments.
- Set your Down payment, expected Interest rate %, and Loan term years.
- Adjust Property tax % / year, Insurance / month, and your Max total DTI %.
- Compare the affordable home price, monthly PITI, and cash to close across the DTI scenarios, then use Download affordability CSV.
Frequently asked questions
How is the affordable price derived?
Your maximum housing payment is monthly income times your DTI limit minus existing monthly debt. The tool then back-solves the loan amount whose principal, interest, and property tax — plus insurance — fits inside that payment, and adds your down payment to get the home price.
What does PITI include here?
Principal and interest from a fixed-rate amortized loan, monthly property tax at your annual rate, and your entered monthly insurance. It does not include PMI or HOA dues, so add those to your monthly debt if they apply.
What DTI should I use?
The scenario table gives common anchors: 36% is a conservative traditional guideline, 43% matches typical qualified-mortgage limits, and 50% is an aggressive stretch. Your entered DTI must be between 1% and 80%.
Why do I see an error about existing debt?
If your monthly debt already consumes the entire DTI allowance, there is no room left for a mortgage payment at that limit — lower the debt figure or raise the DTI to explore other cases.
Is my income data kept on my device?
Yes. The entire calculation, including the CSV, is generated in your browser without any upload.
Is this a pre-approval?
No. Lenders apply credit scores, reserves, PMI, and their own underwriting overlays, so treat these numbers as a planning estimate rather than an offer or financial advice.