Loan Calculator

This loan calculator shows you the monthly payment, total repayment, and total interest for any fixed-rate loan — mortgage, auto, personal, or student. It’s for borrowers comparing offers, planners testing different terms, and anyone who wants to know what a loan truly costs before signing.

How to Use

1. Enter the loan amount: The total principal you plan to borrow
2. Enter the interest rate: The annual percentage rate your lender quotes
3. Enter the loan term: The repayment period in whole years
4. View results: See the monthly payment, total payment, total interest, and interest-to-principal ratio instantly

Features

• Monthly payment computed with the standard amortization formula
• Total interest and total repayment over the full term
• Interest ratio showing how much extra you pay relative to the principal
• Works for any fixed-rate amortizing loan; zero-interest loans handled correctly
• Input validation with clear error messages
• 100% client-side processing

How Amortization Works — and Why Interest Is Front-Loaded

With an amortizing loan, every monthly payment is the same size, but its composition changes over time. Early payments are mostly interest: the bank charges interest on the outstanding balance, and at the start that balance is the whole principal. On a 30-year mortgage, it’s normal for more than half of the first years’ payments to be interest. Only later, as the balance shrinks, does the principal portion grow. This is why extra payments made early in a loan save so much — every extra dollar of principal removes all the future interest that dollar would have attracted.

The loan term matters as much as the rate. Borrow $200,000 at 5% for 30 years and the monthly payment is about $1,074, but you’ll pay roughly $186,500 in interest — nearly doubling the cost. Cut the term to 15 years and the payment rises to about $1,582, yet total interest drops to around $84,700. Shorter terms cost more per month but far less overall, which is exactly the trade-off this calculator lets you test in seconds.

Use Cases

• Mortgage shopping: Compare monthly payments across rates and terms before talking to lenders
• Auto loans: Check whether the dealer’s financing beats your bank’s offer
• Refinancing: See if a lower rate on your remaining balance actually saves money
• Budgeting: Find the maximum loan amount that keeps the payment within your budget

Related Tools

• Percentage Calculator
• Compound Interest Calculator
• Tip Calculator