Loan Calculator — Monthly Payment, Interest & Total Cost
About the Loan Calculator
This calculator works out the fixed monthly payment for an amortizing loan — a mortgage, car loan or personal loan where each payment covers both interest and a slice of principal, so the balance reaches exactly zero at the end of the term.
Enter the loan amount, annual interest rate and term in years. You get the monthly payment, the total interest you will pay, the total cost of the loan, and a summary of how the balance declines over time.
How to use the Loan Calculator
- Enter the loan amount (principal).
- Enter the annual interest rate and the term in years.
- Review the monthly payment, total interest and total repayment — all update live as you experiment.
Amortization formula
M = P · r · (1+r)ⁿ ÷ ((1+r)ⁿ − 1) P = principal · r = monthly rate (annual ÷ 12) · n = number of payments · M = monthly payment Example: $200,000 at 6% for 30 years → r = 0.005, n = 360, M = $1,199.10
Frequently asked questions
Does the payment include taxes and insurance?
No. It is the principal-and-interest payment only. For mortgages, add property tax and insurance to estimate the full monthly cost lenders call “PITI”.
Why does the formula use the monthly rate?
Amortizing loans compound at the payment frequency. The annual rate divided by 12 gives the monthly rate applied to the remaining balance each month.
What happens with 0% interest?
The payment is simply the principal divided by the number of months — the calculator handles that edge case directly.
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