Auto Loan Calculator

To compute your monthly payment, the calculator first determines the net principal loan amount. This is achieved by taking the sticker price of the car, subtracting any down payment (money you have) and your trade-in value adjusted for sales tax savings. Once the loan amount (P) is established, the standard amortization formula is applied: M = P * [r / 12] / [1 - (1 + r / 12)^(-n)], where M represents the monthly payment, r is the annual interest rate expressed as a decimal, and n is the total loan term in months. Finally, the total interest paid is derived by multiplying the monthly payment by the total number of months and subtracting the original loan amount.

Imagine you want to purchase a car priced at $30,000. You have $5,000 in cash for a down payment, and your trade-in vehicle is valued at $4,000. Assuming a local sales tax rate of 6%, your trade-in deduction is calculated first. Your net loan amount equals $30,000 minus $5,000 minus ($4,000 * (1 - 0.06)), resulting in a financed loan amount of $21,240. If you secure a 60-month auto loan at an annual interest rate of 6% (0.06), plugging these figures into the amortization formula yields a monthly payment of approximately $410.59. Over the 5-year life of the loan, you will pay a total of $3,395.40 in interest, bringing your cumulative payments to $24,635.40.

Always secure pre-approval from a credit union or bank before visiting a dealership to gain upper hand negotiating power. Aim for the shortest loan term you can comfortably afford; while a 72 or 84-month term lowers your monthly payment, it significantly increases the total interest paid and risks putting you underwater on the loan. Finally, remember to factor in ongoing ownership costs such as auto insurance, routine maintenance, and fuel when deciding whether a car fits your monthly budget.