This loan payment calculator works for any standard amortizing loan — auto loans, personal loans, student loans, or mortgages. Enter your loan amount, interest rate, and term to see your payment amount, total interest, and how much extra or accelerated payments can save you.
✓ Modify the values and click Calculate to use
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Click "Calculate" to see your results.
How Loan Payments Are Calculated
Standard amortizing loans use a fixed payment that covers both interest and principal so the loan is fully paid off by the end of the term: Payment = P × [r(1+r)^n] / [(1+r)^n − 1], where P is principal, r is the interest rate per period, and n is the total number of payments.
Extra payments go directly toward reducing your outstanding principal, which means less interest accrues in every future period — a compounding savings effect that can save thousands over the life of a loan.
Biweekly payments effectively make 13 monthly payments a year instead of 12 (26 half-payments), automatically accelerating payoff and reducing total interest.
Payment Examples
Standard Auto Loan
$25,000 loan, 6% APR, 5 years, monthly payments.
Monthly Payment
$483.32
Total Paid
$28,999.20
Total Interest
$3,999.20
With a Down Payment
Same loan, but with a $5,000 down payment.
Loan Amount
$20,000.00
Monthly Payment
$386.66
Total Interest
$3,199.36
The down payment saves about $800 in total interest.
Why This Calculator Matters
Auto Loans
See your true monthly payment and total cost before you sign a financing agreement.
Personal Loans
Compare offers from different lenders by looking at total interest, not just the payment.
Paying Off Debt Faster
Model how extra or biweekly payments shorten your payoff timeline and cut interest.
Frequently Asked Questions
Common questions about loan payments and amortization.
How is a loan payment calculated?
Payment = P × [r(1+r)^n] / [(1+r)^n − 1], where P is principal, r is the interest rate per payment period, and n is the total number of payments. This produces a fixed payment covering both interest and principal.
What is the difference between APR and interest rate?
The interest rate is the base cost of borrowing. APR includes the interest rate plus other costs like origination fees and closing costs, giving a more complete picture of the true cost of a loan.
Do extra payments reduce principal?
Yes. Extra payments go directly toward your outstanding principal balance. Since interest is calculated on the remaining principal, reducing it means less interest accrues in every future period — even small extra payments can save thousands over the life of a loan.
Is biweekly better than monthly?
Biweekly payments can save money because you make 26 half-payments per year instead of 12 full payments — effectively 13 monthly payments instead of 12. For a $250,000 loan at 6% over 30 years, this can save over $40,000 in interest and pay it off about 4 years early.
How can I pay off a loan faster?
Make extra payments, switch to biweekly, make one extra lump-sum payment per year, round up your payment, or refinance to a shorter term if rates are favorable.
Does a down payment reduce monthly payments?
Yes. A down payment reduces the principal you need to borrow, directly lowering your monthly payment and total interest paid.
How does loan term affect total cost?
Longer terms mean lower monthly payments but higher total interest. Shorter terms mean higher payments but significantly less total interest paid over the life of the loan.