Decision calculator · private browser tool · mortgage kit export
Mortgage Calculator
Estimate your monthly mortgage payment, compare scenarios, test extra payments, estimate affordability, and export a private mortgage kit with report, JSON, CSV, and Markdown files.
Mortgage Calculator
Calculate · Compare · Export
Property & Loan
Taxes & Insurance
PMI is not auto-estimated because lender rules vary. Enter a monthly PMI amount when applicable.
Income & Debt
Affordability Targets
Estimates target payment, cash required, and max purchase price based on your financials. For guidance only.
Extra Payments
Applied directly to principal. Annual extra is added yearly; one-time extra is added to the first payment.
Principal, interest, taxes, and insurance.
Estimated monthly payment summary not calculated yet.
Charts
Alternative Scenarios
Values are stored locally in your browser session.
Extra Payments Impact
Add optional extra principal in Inputs to estimate payoff acceleration and interest saved.
Monthly Breakdown
Affordability Estimate
Add income, debt, cash, and target ratios to estimate a payment target and cash-to-close range.
Financial Ratios
Amortization (Year 1)
| Month | Payment | Principal | Interest | Balance |
|---|
Mortgage Estimate Report
Generated locally in this browser.
Visual Summary
Text-only summary generated from the current mortgage inputs.
Monthly Breakdown
Alternative Scenarios
Extra Payments Impact
Affordability Estimate
Financial Ratios
Note
This calculator is an estimate only. It does not replace lender, tax, insurance, legal, or financial review.
Local Drafts
Drafts are stored only in this browser with localStorage.
Export Options
Files are generated locally. No data is transmitted.
How to use the mortgage calculator
Enter the home price, down payment, interest rate, loan term, taxes, insurance, and any HOA or PMI assumptions. The calculator updates the payment estimate, scenario comparison, affordability signal, extra-payment impact, and first-12 payment schedule.
- Start with the purchase price and down payment.
- Add the interest rate, term, and start date.
- Include property tax, insurance, HOA, and PMI assumptions.
- Compare scenarios and test extra principal payments.
- Export a report, JSON data, CSV schedule, or Mortgage Kit ZIP.
How mortgage payments are calculated
The principal and interest estimate uses the loan amount, monthly interest rate, and number of payments. Taxes, insurance, HOA dues, and PMI are added separately so the monthly housing estimate is easier to review.
Loan amount
Home price minus the down payment.
Principal and interest
The base loan payment before taxes, insurance, HOA, or PMI.
Total monthly estimate
Principal and interest plus selected monthly housing cost assumptions.
Total interest
The estimated interest paid over the life of the loan before optional extra payments.
What is included in a mortgage payment?
A mortgage payment usually includes principal and interest. Many buyers also budget for property taxes, homeowners insurance, HOA dues, and PMI. This tool separates those assumptions so you can see what is driving the monthly estimate.
How much house can I afford?
The affordability mode compares income, existing debt, available cash, closing cost assumptions, and target housing/debt ratios. The estimate is a planning guide, not a loan approval or financial advice.
What extra payments do to interest and payoff time
Extra principal payments lower the loan balance faster. That can reduce total interest and shorten payoff time. The app can test monthly, annual, and one-time extra principal assumptions.
15-year vs 30-year mortgage comparison
A shorter term often has a higher monthly payment but lower total interest. A longer term usually has a lower monthly payment but higher total interest. Scenario cards help compare payment, interest, DTI, and cash assumptions side by side.
What is cash to close?
Cash to close is the estimated amount needed at closing, usually including the down payment and closing costs. The calculator includes a cash-to-close gap so you can compare available cash against the selected assumptions.
Important limits
This calculator is for planning and education. It is not a lender quote, underwriting decision, appraisal, tax advice, legal advice, or financial advice. Actual payments and costs depend on lender terms, location, taxes, insurance, fees, and borrower qualification.
Mortgage calculator FAQ
What will my mortgage payment be?
Your payment depends on the home price, down payment, loan term, interest rate, property tax, homeowners insurance, HOA dues, and PMI assumptions. The calculator estimates principal and interest plus common monthly housing costs.
What is included in a monthly mortgage payment?
A monthly payment commonly includes principal, interest, property taxes, homeowners insurance, HOA dues when applicable, and PMI when the down payment is below the selected threshold.
How much house can I afford?
The affordability estimate compares your target housing ratio, total debt ratio, available cash, down payment, and closing cost assumptions. It is guidance only and is not lender approval.
How do extra mortgage payments affect payoff time?
Extra principal payments can reduce interest and shorten the payoff schedule because more of the payment goes toward lowering the loan balance.
Can I export my mortgage estimate?
Yes. The tool can export a mortgage kit with a printable HTML report, Markdown report, JSON data, first-12 payment schedule CSV, and first-12 payment schedule Markdown.
Does this calculator upload my mortgage inputs?
No. This tool is designed to run in your browser. Inputs, local drafts, and exports are handled locally by this tool unless you choose to share or upload exported files elsewhere.
Agent action map
Structured controls and outputs for browser agents, accessibility tools, and workflow automations.
- Home price field
- Down payment field
- Interest rate field
- Loan term field
- Property tax field
- Insurance field
- Monthly income field
- Other monthly debt field
- Extra monthly principal field