How to Calculate Monthly Loan Payments

Calculate loan payments in seconds

Before you sign for a car, a mortgage, or a personal loan, you want one number: the monthly payment. Knowing it tells you whether the loan fits your budget and lets you compare offers from different lenders on equal footing. The payment depends on just three things — how much you borrow, the interest rate, and how long you take to repay it — but the math that ties them together isn't something you can do in your head.

This guide shows you how to calculate loan payments in a few seconds using a free online calculator, and it explains the formula underneath so the number makes sense even when you're away from the tool. Everything below runs right in your browser, so the figures you type stay on your device — nothing is uploaded and there's no sign-up.

How to calculate your monthly loan payment

1. Open the loan payment calculator. It loads instantly in your browser with a few sensible defaults already filled in.

2. Pick the loan type. Choose Mortgage, Auto, Student, or Personal. This just sets a reasonable starting interest rate and term for you — you can override both. If you're shopping for a vehicle specifically, the dedicated car loan calculator is tuned for that case.

3. Enter the loan amount (principal). Type the amount you actually plan to borrow — that's the purchase price minus any down payment or trade-in. For a $35,000 car with $5,000 down, enter 30000.

4. Enter the interest rate. Use the APR your lender quoted, as an annual percentage (for example, 7.5). If you only have a quote in another form, use whatever annual rate the lender lists.

5. Set the loan term. Enter the length of the loan and choose years or months. A 5-year auto loan is 5 years; a 30-year mortgage is 30 years.

6. Read your monthly payment. The result updates as you type. You'll see the monthly payment, the total of all payments over the life of the loan, and the total interest you'll pay — that last figure is the real cost of borrowing.

7. Check the amortization schedule. Open the amortization tab to see how each payment splits between principal and interest, month by month. Early on most of your money goes to interest; later it flips toward principal. For a full month-by-month table you can also use the standalone amortization schedule.

8. Test "what-ifs." Add an extra monthly payment, or switch to biweekly payments, and watch how much interest you save and how many months come off the term. Use the compare tab to put two loan scenarios side by side before you commit.

The formula behind the number

The calculator uses the standard fixed-payment (amortizing) loan formula:

M = P × r × (1 + r)ⁿ / ((1 + r)ⁿ − 1)

• M is the monthly payment.
• P is the principal (the amount borrowed).
• r is the monthly interest rate — the annual rate divided by 12. So 6% per year becomes 0.06 / 12 = 0.005.
• n is the total number of payments — years × 12. A 30-year loan is 360.

Quick example: borrow $20,000 at 6% for 5 years. Then r = 0.005 and n = 60. Plugging in gives a monthly payment of about $386.66. Over 60 months that's roughly $23,200 paid, so about $3,200 of interest.

One special case: if the rate is 0%, the formula breaks (you'd divide by zero), so the payment is simply principal divided by the number of months. The calculator handles that automatically.

Tips

• Use APR, not the nominal "interest rate," when you can. APR folds in certain fees, so it reflects the true annual cost more honestly across lenders.
• A longer term lowers the monthly payment but raises total interest. Stretching a loan from 4 to 6 years feels cheaper each month but can cost thousands more overall — watch the total-interest figure, not just the monthly one.
• Small extra payments compound. Even $50 extra a month goes straight to principal and can shave months off the loan. Test it in the extra-payment field before deciding.
• For mortgages, payment isn't the whole story. The loan calculator gives principal and interest only. Property taxes, homeowners insurance, and PMI are extra — the mortgage calculator is built to include those.

Common problems

• The payment looks too low. Double-check the term unit. Entering 360 with "years" selected instead of "months" will stretch the loan to 360 years and produce a tiny, meaningless payment.
• The rate field. Enter 7.5 for 7.5%, not 0.075. The tool treats the number as a percentage.
• You forgot the down payment. Principal is what you borrow, not the sticker price. Subtract your down payment or trade-in first.

FAQ

Does this calculator save or send my numbers anywhere? No. The calculation runs entirely in your browser. The amounts and rates you enter stay on your device — nothing is uploaded and there's no account to create.

Why is so much of my early payment going to interest? Interest is charged on the outstanding balance, which is highest at the start. Each payment chips away a little principal, so the balance — and the interest portion — shrinks over time while the principal portion grows. The amortization tab shows this shift clearly.

Can I use it for any loan type? Yes, for any standard fixed-rate amortizing loan: personal, auto, student, or mortgage. For car-specific or mortgage-specific extras (like taxes and insurance), the car loan and mortgage calculators add those fields.

How do extra payments save money? Extra money goes entirely to principal, lowering the balance faster. Since future interest is based on that smaller balance, you pay less interest and finish the loan sooner. Try a few amounts in the extra-payment field to see the savings.

Want to see how a balance grows instead of shrinks? Try the compound interest calculator for savings and investments.