Loan Monthly Payment Calculator

How a loan payment is calculated

Most consumer loans — car loans, personal loans, fixed-rate mortgages — are amortized. That means you pay the same amount every month, and each payment covers the interest that has accrued plus a little of the principal. Early on, most of your payment is interest; later, most of it goes to principal. This calculator uses the standard amortization formula to find that fixed monthly payment from three inputs: the amount borrowed, the annual interest rate, and the term in years.

The formula

With principal P, monthly rate i (the annual rate ÷ 12 ÷ 100), and number of payments n (years × 12):

payment = P × i ÷ (1 − (1 + i)−n)

When the interest rate is 0%, that formula would divide by zero, so the payment is simply the principal split evenly across the months. The calculator handles that case automatically.

What the results tell you

• Monthly payment — what you pay each month for the life of the loan.
• Total interest — the extra you pay on top of what you borrowed.
• Total of payments — principal plus interest, the true cost of the loan.

A longer term lowers the monthly payment but raises the total interest — sometimes dramatically. Try the same loan over 3, 5, and 7 years to see the trade-off between an affordable payment and the total cost.

Important limitations

This is an estimate for a fixed-rate, fully amortizing loan. It does not include fees, insurance, taxes, PMI, or the effect of a variable rate, and it assumes payments are made on schedule. For a real quote, always use the lender’s figures and the APR, which folds in certain fees.

FAQ

Is the rate I enter the APR?

Enter the nominal annual interest rate. APR can be slightly higher because it includes some fees, so the lender’s payment may differ a little from this estimate.

Does it work for mortgages?

Yes, for the principal-and-interest portion of a fixed-rate mortgage. Remember that a real mortgage payment usually also includes property tax and insurance.

Why is so much of my early payment interest?

In an amortizing loan, interest is charged on the remaining balance, which is highest at the start. As the principal shrinks each month, the interest portion falls and more of your fixed payment goes to principal, which is why progress feels slow at first.

Can I use it for a zero-interest loan?

Yes. At 0% the standard formula would divide by zero, so the calculator simply splits the principal evenly across the number of months, and the total interest comes out as zero.

How can I pay less interest overall?

A shorter term raises the monthly payment but sharply cuts total interest, so try the same loan over 3, 5, and 7 years to compare. Extra payments toward principal also reduce the interest you pay, though this estimate assumes only the scheduled payments.

Is it free and private?

Yes, it is free with no sign-up, and the calculation runs in your browser, so your loan figures are never uploaded. It works on phones and desktops alike.