What this calculator does
The loan payment calculator turns three inputs (your loan amount, interest rate, and term) into a clear monthly payment estimate. It works for most fixed-rate loans, including personal loans, auto loans, and student loans. Adjust any field and the results update right away, so you can see how a lower rate or a shorter term changes what you pay each month and over the life of the loan.
Enter the loan amount
Type the total you plan to borrow, for example $20,000. If you have a down payment or trade-in, subtract it first and enter only the amount you actually need to finance.
Add the interest rate
Enter the annual interest rate your lender quoted, such as 8%. If you only have an APR, you can use it here for a close estimate, since APR includes most fees rolled into the rate.
Set the loan term
Choose how long you will repay, usually in months or years. A common personal loan term is 3 to 5 years. Shorter terms raise the monthly payment but cut the total interest you pay.
Review your results
The calculator shows your estimated monthly payment, the total interest, and the total amount repaid. Change any field to compare scenarios side by side.
How the monthly payment is calculated
Most fixed-rate loans use an amortization formula. It spreads your balance into equal monthly payments, where early payments cover more interest and later ones cover more principal. In plain terms, the calculator takes your monthly interest rate (the annual rate divided by 12) and your number of payments (the term in months), then solves for the fixed amount that pays the loan off exactly on schedule.
Worked example: Say you borrow $20,000 at 8% for 5 years (60 monthly payments). The monthly rate is about 0.6667% (8% divided by 12). Run those numbers and the payment comes to roughly $405.53 per month. Over the full term you repay about $24,332, which means around $4,332 goes to interest on top of the $20,000 you borrowed.
What changes your monthly payment
Three levers move your payment. Loan amount: borrowing more raises both the monthly payment and the total interest. Interest rate: even a one-point difference adds up over years, so it pays to compare offers. Term: stretching the loan over more months lowers each payment but increases the interest you pay overall. The calculator lets you test each lever, so you can find a payment that fits your budget without overpaying in the long run.
Look at the total cost, not just the payment
A low monthly payment can feel affordable while quietly costing more. A longer term shrinks the payment but adds months of interest, so two loans with the same rate can differ by hundreds or thousands of dollars in total. Before you commit, check the total interest and total repaid figures, not only the monthly number. The cheapest payment and the cheapest loan are not always the same thing.
Tips for an accurate estimate
Use the rate you were actually quoted, not an advertised teaser rate, for a realistic number.
Check whether your loan carries fees such as an origination charge, since they raise your true cost even when the monthly payment looks the same.
Try a shorter term to see how much interest you could save, then weigh it against the higher payment.
Add any extra monthly payment you can afford. Even small amounts applied to principal shorten the loan and cut interest.
Compare a few lenders using the same amount and term so you are comparing like for like.
Loan payment calculator FAQ
How is a monthly loan payment calculated?
It uses an amortization formula that combines your loan amount, monthly interest rate, and number of payments into one fixed monthly figure. Each payment covers the interest due that month, and the rest reduces your balance. Early in the loan more goes to interest, and later more goes to principal.
What is the difference between interest rate and APR?
The interest rate is the cost of borrowing the principal, while the APR also folds in certain fees to show the yearly cost more completely. APR is usually a little higher than the rate. For a quick estimate you can enter either, but the APR gives you a closer picture of total cost.
Does a longer loan term lower my monthly payment?
Yes. Spreading the same balance over more months reduces each payment. The trade-off is that you pay interest for longer, so the total cost of the loan goes up. Use the calculator to see both numbers before you decide.
Will paying extra each month save me money?
Usually, yes. Extra payments go straight to your principal, which shrinks the balance interest is charged on and shortens the loan. Check that your lender does not charge a prepayment penalty first, then put any spare money toward the balance.
How much can I afford to borrow?
Start with a monthly payment that fits comfortably in your budget, then adjust the loan amount and term until the calculator lands near that figure. A common guideline is to keep total debt payments well within your monthly income, but the right number depends on your other expenses and goals.