About the Mortgage Calculator
Estimate monthly fixed-rate mortgage payments and assess how down payments and extra principal payments change costs.
Formula or method
Calculate financed principal as property price minus down payment. Apply the monthly amortizing loan formula using annual rate divided by twelve, and add entered annual tax and insurance divided by twelve.
Worked example
For a 400,000 property, 80,000 down, 30 years and 5.5% interest, compare monthly principal and interest with optional taxes and insurance.
How to use the tool
- Enter the requested settings or select a supported input file.
- Use the tool controls to calculate, process or record your results.
- Inspect the output and download it when supported.
Common uses
Everyday personal calculations, basic document preparation, timekeeping and image editing.
Assumptions and limitations
Excludes PMI, HOA, closing fees, escrow timing and lender-specific changes. The model assumes fixed interest and payments; variable mortgages require a different model.
Frequently asked questions
Does the monthly total include property taxes?
Only if you enter estimated annual property tax and insurance amounts; many other costs are not included.
Privacy and support
Your inputs are processed locally in your browser. ToolMosaic does not upload or store the values you enter in this tool. Our tools are free, and we appreciate your support.