What is a mortgage?
A mortgage calculator estimates the recurring cost of borrowing to purchase a home. Adjust the deposit, interest rate and repayment term to understand how each assumption changes the monthly principal-and-interest payment. Add annual property tax and home insurance for a broader monthly housing estimate.
Formula and calculation method
Monthly principal and interest = P × r × (1 + r)^n ÷ ((1 + r)^n − 1). P is the amount borrowed, r is the monthly interest rate and n is the number of monthly payments.
The result is only as reliable as the inputs and assumptions. This tool is educational and does not replace professional financial, medical, legal or academic advice.
How to use this calculator
- Enter the values requested in the calculator.
- Review the result panel; it updates when an input changes.
- Change one assumption at a time to compare scenarios.
- Check the formula and limitations before acting on the estimate.
Frequently asked questions
Is this mortgage calculator free?
Yes. You can use this calculator in your browser without creating an account.
How accurate is the result?
It applies the displayed formula to the values you provide. Real-world outcomes can differ because of fees, changing rates, individual circumstances or rules not represented in this estimate.
Are my inputs stored?
No. The calculation runs locally in your browser and the values are not submitted to FastSEOHub.