How the mortgage calculator works
A mortgage payment is made up of principal (the amount you borrowed) and interest (the cost of borrowing). This calculator uses the standard amortization formula to work out a fixed monthly payment that pays off your loan over the full term, then shows how each payment is split between interest and principal over time.
Enter your loan amount, annual interest rate, and term in years to see your estimated monthly payment, total interest paid, and a full amortization schedule. You can compare different rates and terms to understand how each choice changes the lifetime cost of your loan.
What affects your monthly payment
Three inputs drive your payment the most: the loan amount, the interest rate, and the loan term. A longer term lowers the monthly payment but increases the total interest you pay; a shorter term does the opposite.
- Loan amount: the price of the home minus your down payment.
- Interest rate: even a 0.5% difference can change total interest by thousands.
- Term: 15-year loans cost less overall but have higher monthly payments than 30-year loans.
- Extra payments: paying more than the minimum reduces principal faster and saves interest.
Understanding amortization
Early in the loan, most of each payment goes toward interest because the outstanding balance is high. As the balance falls, more of each payment goes toward principal. This is why making extra payments in the first years has the biggest impact on total interest.
Frequently asked questions
Does this calculator include taxes and insurance?
The core calculation focuses on principal and interest. Property taxes, homeowners insurance, HOA dues, and mortgage insurance vary widely by location and lender, so add them separately to estimate your full monthly housing cost.
How much can extra payments save me?
Extra payments go straight to principal, which reduces the balance that interest is charged on. Even a small recurring extra payment can shorten your loan by years and save a significant amount of interest over the life of the mortgage.
Is the result an exact quote?
No. It is an estimate to help you plan and compare scenarios. Your actual rate and payment depend on your credit profile, down payment, loan type, and the lender’s terms.
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This content is provided for general educational purposes only and does not constitute financial, tax, or legal advice. Rates, limits, and regulations change over time. Verify figures with an official source or a qualified professional before making decisions.