Loan Calculator

Work out the monthly payment, total interest and payoff schedule for a personal loan, student loan or any fixed-rate installment loan.

  • Reviewed October 2026
  • Formula and worked example below
  • Free, no sign-up, runs in your browser
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Optional. Many personal loans charge 1–8% up front.
Enter your numbers to see the result.

How loan payments work

Most personal, student and auto loans are amortizing loans: you pay the same amount every month, and by the last payment the balance is exactly zero. The monthly payment depends only on the amount you borrow, the interest rate and the number of payments.

Payment = P × r ÷ (1 − (1 + r)^−n)

Here P is the loan amount, r is the annual rate divided by 12 and n is the number of monthly payments. If the rate is zero, the payment is simply P ÷ n.

Example

Borrowing $25,000 at 9.5% for 5 years gives r = 0.0079167 and n = 60. The monthly payment is $525.05. Over five years you pay $31,503 in total, so the loan costs $6,503 in interest. Stretching the same loan to 7 years cuts the payment to $408.60 but raises total interest to about $9,322.

Interest rate vs APR

The interest rate is the cost of borrowing the principal. The annual percentage rate (APR) also folds in required fees such as origination charges, so it is the better number for comparing offers. If a lender deducts a 5% origination fee, you receive only $23,750 of a $25,000 loan but repay the full amount. Enter the fee in the optional field to see the true total cost.

Tips before you borrow

  • Check your rate with several lenders; most use a soft credit check that does not affect your score.
  • Choose the shortest term whose payment fits comfortably in your budget.
  • Ask whether early repayment is allowed without a penalty. Paying extra each month shortens the loan and reduces interest.
  • Keep total debt payments, including this loan, under about 36% of your gross monthly income.

Frequently asked questions

How is the monthly loan payment calculated?

The calculator uses the standard amortization formula: Payment = P × r ÷ (1 − (1 + r)^−n), where P is the loan amount, r is the monthly interest rate and n is the number of payments.

Does a longer loan term save money?

No. A longer term lowers the monthly payment but increases the total interest you pay, because you borrow the money for longer.

Can I use this for student loans or car loans?

Yes. Any fixed-rate loan with equal monthly payments works. For car purchases, the auto loan calculator also handles trade-ins and sales tax.

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Last reviewed Oct 20, 2026. Results are estimates; check important decisions with a qualified professional.