How Loan Interest and Monthly Payments Work
Every loan payment you make covers two things: a portion of the principal you borrowed and the interest charged on the remaining balance. Understanding how these two components interact lets you compare loan offers intelligently and spot the true cost of borrowing before you sign.
How monthly payments are calculated
Lenders use a fixed payment formula that keeps your monthly payment the same throughout the loan term. Early payments are mostly interest; later ones are mostly principal. This is why paying even a little extra early in a loan term can dramatically reduce total interest paid.
APR vs. interest rate
The interest rate is the cost of borrowing the principal. APR (Annual Percentage Rate) is broader — it includes the interest rate plus fees like origination charges and points. Always compare APRs when shopping loans, not just interest rates, to get an apples-to-apples view of total cost.
Using the loan calculator
Enter the loan amount, annual interest rate, and repayment term into the loan calculator. It shows your fixed monthly payment, total interest over the life of the loan, and a full amortization schedule so you can see exactly how each payment breaks down.