Finance

Loan Payment Calculator

What this does

Work out the monthly payment, total interest and payoff cost for any fixed-rate installment loan.

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Where this applies

Personal loans, debt consolidation, student-style installment plans and many point-of-sale financing offers use this same structure. If a lender quotes “APR”, you can drop it straight into this calculator.

Watch the total cost, not just the payment

Longer terms shrink the monthly payment but grow total interest. Comparing “total repaid” between two terms is usually more revealing than comparing payments alone.

The math behind this calculator

M = P · r / (1 − (1 + r)^−n)

Uses the standard amortizing-payment formula with the monthly rate r = APR ÷ 12 and n equal to the number of monthly payments. Every payment first covers that month’s interest; the rest reduces the balance.

Assumptions & limitations

  • Fixed APR and equal monthly payments.
  • No origination fees or prepayment penalties are modeled.
  • A 0% rate divides the principal evenly across the term.

Worked example

Borrowing $25,000 at 9.5% APR over 48 months costs $628.08 per month with $5,147.76 total interest.

Frequently asked questions

What is the difference between APR and interest rate?
APR folds certain fees into an annualized rate, so it better reflects the true borrowing cost. If your lender quotes both, use the APR here.
Does paying early save money?
With simple-interest amortizing loans, yes; extra principal payments shorten the term and cut remaining interest, assuming no prepayment penalty.
Can I use years instead of months?
Multiply years by 12 before entering the term.

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