Auto Loan Calculator

Introduction

This Auto Loan Calculator estimates monthly payment, total interest, and total cost of financing a vehicle purchase. Enter vehicle price, down payment, trade-in value, sales tax rate, APR, and loan term in months. The tool computes amount financed after credits and tax, then amortizes the loan at the stated rate. Use it to compare dealer worksheets, credit union pre-approvals, and cash versus finance decisions before you sign a retail installment contract.

Who this calculator is for

Car buyers reviewing F and I office worksheets who want an independent payment check. Private-party purchasers negotiating with a bank pre-approval also use it to see how down payment changes payment. Lessees comparing buy versus finance should pair results with the Auto Lease Calculator. Shoppers weighing rebate versus low APR offers use the Cash Back or Low Interest Calculator.

Skip if you are modeling business fleet depreciation or Section 179; this is consumer retail finance math. Insurance, registration, and extended warranties are usually outside amount financed unless rolled into the loan.

What it estimates

Amount financed equals vehicle price minus down payment and trade-in, plus taxable amount times tax rate if tax is financed, minus rebates if entered. Monthly payment uses standard amortization: fixed payment splits interest and principal each month until balance reaches zero at term end. Total interest is sum of interest portions; total cost includes principal, interest, and down payment out of pocket.

Dealer may use different day-count, first payment timing, or doc fees in amount financed. Doc fees and gap insurance rolled into loan increase payment; add them if your worksheet includes them. Zero percent APR promos still may carry shorter terms or higher price.

Inputs explained

APR is annual percentage rate for the loan, not money factor. Term is months, commonly 48, 60, 72, or 84.

• Vehicle price: Negotiated selling price before tax, often called sale price on worksheet.
• Down payment: Cash paid upfront reducing amount financed.
• Trade-in value: Allowance applied to deal; enter net if payoff exceeds value elsewhere.
• Sales tax rate: Local rate if tax is financed into loan.
• APR: Annual interest rate on the retail installment contract.
• Loan term: Number of monthly payments.

How to read the results

Monthly payment is what leaves your checking account for principal and interest only. Total interest shows cost of borrowing over the full term; longer terms lower payment but raise interest. Amount financed line should match dealer within a few dollars; large gaps mean doc fees, products, or tax treatment differ.

Compare 60 versus 72 month terms at same APR to see interest delta. If payment at 60 months strains budget, consider less car rather than longer term automatically. Read auto loan financing tips for pre-approval strategy.

Worked example

Vehicle price $38,500, down payment $4,000, trade-in $2,500, sales tax 7%, APR 6.9%, term 60 months. Taxable base roughly $32,000 before tax, sales tax about $2,240 if applied to net price after trade and down. Amount financed near $34,240 depending on whether tax is on full price or net. Monthly payment about $675 to $685. Total interest over five years roughly $6,200 to $6,800.

Raise APR to 9.9% and payment climbs toward $725 with interest over $9,000. Add $1,500 doc and products to financed amount and payment rises about $30 per month at 6.9%. Zero down increases interest paid because principal stays higher longer.

Practical use cases

Credit union pre-approval: match their APR and term to dealer offer. Trade-in negotiation: see payment impact of $500 more trade value. Refinance check: enter remaining balance as price, zero down, new APR and remaining months.

Cash buyer sanity check: compare total paid including interest versus cash price net of rebate using cash-back calculator. Budget fit: feed payment into monthly budget alongside insurance and fuel.

Limitations and related tools

Does not model early payoff penalties rare in auto, gap refunds, or negative equity rolled from prior loan unless you reduce trade-in net manually. Subprime tiered APR, balloon notes, and lease-buyout loans may need custom fields.

Also use Auto Lease Calculator, Cash Back or Low Interest Calculator. Article: auto loan financing tips.

How It Works

1. Enter vehicle price and credits. Type sale price, down payment, and trade-in allowance from your worksheet.
2. Add tax rate and APR. Enter local sales tax if financed and the APR from lender or dealer.
3. Set loan term in months. Choose 48, 60, or other term offered on the contract.
4. Review payment and total interest. Calculate and compare monthly payment and total interest to alternative terms or offers.

Formula and methodology

The Auto Loan Calculator uses this identity for the scenario you enter. A bank, payroll system, or tax program may round on a 360-day year or average daily balance, so a statement can differ by a small amount.