Auto Loan Calculator

How a car loan calculator works

A car loan calculator turns four numbers into a monthly payment: the amount you actually borrow, the interest rate the lender is charging, how many months you take to pay it back, and whether any fees or taxes are rolled into the loan. The math is the standard amortization formula used for mortgages and personal loans. Every month, part of your payment covers interest on the remaining balance and the rest chips away at principal.

The amount you finance is not the sticker price

Start with the vehicle price, subtract your down payment, then subtract the trade-in credit your dealer is giving you. In most states, sales tax is charged only on the difference between the new car price and the trade-in, which is a real savings. Add that sales tax and any fees you roll into the loan (registration, doc fees, gap insurance). The result is the amount financed, and that is the number the payment calculation uses.

APR vs interest rate

Enter the APR the lender quotes on your loan agreement, not just the nominal interest rate. APR bundles the interest rate with most loan fees, so it gives a more accurate picture of what the loan actually costs. A slightly higher APR over a long term can quietly add thousands of dollars to the total interest you pay.

Loan term is the biggest lever on monthly payment

Stretching a car loan from 60 to 84 months can shave a hundred dollars or more off the monthly payment, which is why dealers love to lead with long terms. The tradeoff is real. You pay interest for longer, you owe more than the car is worth for longer (this is called being underwater or having negative equity), and if you total the car early you can end up writing a check to the lender for the difference. As a general rule, a 60 month loan is a reasonable ceiling for a new car and 48 months or less is safer for a used car.

Down payments do more than lower the payment

A larger down payment reduces the amount financed, which lowers the monthly payment and cuts the total interest you pay. It also gives you an equity cushion, so a minor accident or a fast-depreciating first year does not leave you upside down. A common target is 20 percent down on a new car and 10 percent down on a used car.

What this calculator does not include

• Insurance premiums, which vary widely by driver and vehicle.
• Fuel, maintenance, and repair costs.
• State-specific fees such as personal property tax on vehicles.
• Rebates or manufacturer incentives that reduce the price before financing.

Use this tool to compare scenarios: a bigger down payment vs a longer term, a promotional 3.9 percent APR vs a 7.5 percent bank loan, a new car with a 60 month loan vs a certified used car with a 48 month loan. Small changes in APR and term compound into real money over the life of the loan.