What this calculator does
Enter the amount, the annual interest rate and the term, and it shows the three numbers a loan quote often hides in plain sight: the monthly payment, the total interest you will pay over the life of the loan, and the total amount repaid. Add an optional extra monthly payment to see how much faster the loan clears and how much interest that saves — on a long loan, the answer usually surprises people.
The rate must be reducing-balance
This tool assumes the rate you enter is a reducing-balance rate — interest charged on what you still owe, which is how most bank loans and mortgages work. Some lenders, particularly for personal and vehicle loans, quote a flat rate instead: interest charged on the original amount for the whole term. A flat rate is much more expensive than the same number quoted reducing-balance — roughly speaking, a flat rate is comparable to a reducing-balance rate of nearly twice the number. If your quote is a flat rate, do not type it in here directly; ask the lender for the total repayable and compare that against this calculator's output instead. Our guide to reading a loan agreement explains the difference in full.
Why total interest matters more than the payment
Lenders sell the monthly payment because it is the number that fits a budget. But two loans with the same monthly payment can have very different total costs — a longer term shrinks the payment while growing the interest. The total-interest figure is the honest price of the loan, and it is the number to compare offers on.
| Change | Effect on payment | Effect on total interest |
|---|---|---|
| Longer term | Lower | Higher — often dramatically |
| Lower rate | Lower | Lower |
| Extra monthly payment | Higher (by the extra) | Lower, and the loan ends sooner |
What it deliberately leaves out
Real loans carry more than interest: initiation fees, monthly service fees, credit life insurance and disbursement charges. These differ by lender and by country, so a generic tool cannot price them honestly — but they can add a meaningful share to the true cost, especially on smaller loans. When comparing real offers, always ask for the total cost of credit in writing.
This tool runs entirely in your browser — nothing you type is sent to us or stored. Results are estimates for education, not financial advice; real products carry fees and taxes this generic tool cannot know. More tools: see the full list.