Mortgage calculator guide
This mortgage calculator estimates the monthly cost of a home loan using the standard amortization formula. It separates principal and interest from optional housing costs such as property tax, insurance, and HOA fees, so the result is easier to compare with your actual budget.
How to use it
- Enter the home price and down payment to calculate the loan amount.
- Use the annual interest rate quoted by your lender or a conservative estimate.
- Select a 15, 20, or 30 year term to see how the payment and total interest change.
- Add property tax, insurance, HOA, and extra payment only if you want a fuller housing-cost estimate.
Calculation method
P is the loan amount, r is the monthly interest rate, and n is the total number of monthly payments. Taxes and insurance are added after the principal-and-interest payment.
Example scenario
A $400,000 home with $80,000 down, a 6.5% rate, and a 30-year term produces a principal-and-interest payment of roughly $2,023 per month. Adding estimated tax and insurance gives a more realistic housing-cost number.
What to watch
This is an estimate, not a loan quote. It does not include every possible cost such as mortgage insurance, lender fees, closing costs, rate buydowns, or local rules. Use it for planning and comparison, then confirm final numbers with your lender.
How to use this calculator
- Enter realistic values that match your current situation.
- Press Calculate to refresh the estimate.
- Compare the main result with the supporting details in the result panel.
- Change one input at a time to see which variable affects the result most.
FAQ
Is a 15-year mortgage always better?
Not always. A 15-year loan usually has less total interest, but the monthly payment is higher. A 30-year loan gives more cash-flow flexibility.
Does extra payment really matter?
Yes. Extra principal payments reduce the balance faster, which can cut years off the payoff schedule and lower total interest.
Should I include taxes and insurance?
For affordability planning, yes. For pure loan comparison, look at principal and interest separately.