Loan Payment Calculator
Work out the payment, total interest, and total cost of any loan. e.g. “What are the monthly payments on a $20,000 loan?”
Enter your values
Results update as you type. All calculation happens in your browser.
Methodology
Work out the payment, total interest, and total cost of any loan. This tool uses a standard, documented formula and runs entirely on your device.
Last reviewed January 2026 · Runs client-side
How loan payments and total interest work
Any fixed-rate installment loan, personal, auto, or otherwise, is repaid with equal periodic payments. Each payment covers the interest accrued that period plus a slice of the principal. Because the balance shrinks over time, the interest portion falls and the principal portion grows, even though the payment stays the same.
The headline figure people compare is the monthly payment, but the total interest tells the real story of what borrowing costs. A longer term lowers the payment while raising the total interest, so it pays to look at both together before choosing a term.
How to use this calculator
- Enter the amount you are borrowing and the annual interest rate.
- Set the term in years and choose how often you pay.
- Read the payment, the number of payments, and the total interest.
What the inputs mean
- Loan amount
- The principal you borrow, before any interest.
- Interest rate
- The annual percentage rate, entered manually.
- Payment frequency
- Monthly, bi-weekly, or weekly. More frequent payments slightly reduce total interest.
A $20,000 loan at 8.9% over five years works out to about $414 per month, with roughly $4,850 of total interest across 60 payments.
The formula, in plain terms
Payment = A·r(1+r)ⁿ / ((1+r)ⁿ−1), where A is the loan amount, r is the rate per period, and n is the number of payments.
Good to know
- Extending a term to lower the payment almost always increases total interest.
- Compare offers on total interest and total repayment, not just the monthly figure.
Frequently asked questions
Is APR the same as interest rate?
Not always. APR can include certain fees, so a loan's APR may be higher than its base rate. Enter the rate your lender specifies for the payment calculation.
Does paying bi-weekly save money?
Slightly, because interest compounds on a smaller average balance and you make the equivalent of an extra payment per year.
Last reviewed January 2026. This explainer is general information, not professional advice.