Total Car Loan Cost Calculator: Payment, Interest and Fees

A total car loan cost calculator estimates your monthly payment and the total of those payments from the amount financed, APR, and loan term. Enter the figures from a lender’s quote to see total interest as well; this estimate does not include vehicle taxes, fees, or other costs unless they are already included in the loan amount.

Formula

The calculator uses the standard fixed-payment loan formula. It calculates a monthly payment, rounds that payment to the nearest cent, then multiplies it by the number of monthly payments to estimate the total paid. Total interest is the payment total minus the amount borrowed.

• p is the amount financed, in dollars.
• apr is the annual percentage rate entered as a percentage, such as 8 for 8% per year.
• r is the monthly rate: apr / 1200.
• n is the number of payments: loan term in years × 12.
• pmt is the monthly payment, in dollars: round[p × r / (1 − (1 + r)⁻ⁿ), 2].
• tot is total of payments, in dollars: pmt × n.
• int is estimated total interest, in dollars: tot − p.

The APR is divided by 1,200 to convert a yearly percentage into a monthly decimal rate. The formula assumes equal monthly payments and a fixed rate. A lender’s payment schedule may differ if its rounding, payment dates, or loan structure differs.

Worked Example

Using the calculator’s default values—$20,000 financed, 8% APR, and five years—the loan has 60 monthly payments.

1. Convert APR to a monthly rate: 8 / 1,200 = 0.0066667.
2. Calculate the payment: $20,000 × 0.0066667 / [1 − (1 + 0.0066667)⁻⁶⁰] = about $405.53 per month, rounded to cents.
3. Calculate total payments using the rounded monthly amount: $405.53 × 60 = $24,331.80.
4. Subtract the amount financed: $24,331.80 − $20,000 = $4,331.80 estimated interest.

These outputs distinguish the borrowed amount from the cost of borrowing. The total of payments includes principal and interest, while the total-interest figure excludes the principal.

Assumptions

• The interest rate stays fixed for the full term.
• Payments are equal, made monthly, and begin on a regular schedule.
• Interest is modeled monthly at APR / 12.
• Fees, taxes, insurance, optional products, and any down payment or trade-in are not separately modeled. A fee financed into the loan should be reflected in the amount financed.

What Counts Toward Total Car Loan Cost?

“Total car loan cost” can mean more than one figure. This calculator defines the loan’s total paid as the sum of its scheduled payments. That total includes principal and modeled interest, but it is not necessarily the full cost of buying and owning a vehicle.

To estimate the amount financed, start with the agreed vehicle price and add any costs being financed, then subtract the down payment, trade-in credit, or other money applied at purchase. The exact treatment of taxes, fees, credits, and optional products depends on the transaction paperwork. Use the amount labeled “amount financed” on a lender’s disclosure when available, rather than assuming the vehicle’s sticker price is the loan principal.

Costs paid separately—such as insurance, fuel, maintenance, registration, or a deposit—are outside this loan-payment calculation. If you want an ownership-cost estimate, account for those separately and avoid adding an item twice if it is already financed.

How to Use and Read the Calculator

• Enter the amount borrowed, not automatically the vehicle’s advertised price.
• Enter APR as a percentage: use 8 for 8%, not 0.08.
• Enter the loan term in years. The calculator converts it to monthly payments.
• Compare the monthly payment, total payments, and total interest with the figures in the lender’s quote.

A lower monthly payment by itself does not show that a loan costs less overall. For the same principal and rate, a longer term spreads repayment across more months; the payment is generally lower, but the borrower pays interest for longer. Compare both the payment and the total of payments, with the same amount financed and APR, when examining different term scenarios.

The outputs are estimates, not a quote or payoff balance. The displayed total uses the monthly payment rounded to cents and assumes every payment follows the modeled schedule. Actual final payments can vary because of payment dates, lender calculations, fees, or adjustments to the loan.

Common Input Problems and Limits

Small input mistakes can materially change the result. Check that the APR is the annual rate stated in the offer, not a monthly rate or a bare decimal. Check the term’s unit as well: five years means 60 monthly payments, while entering 60 as years would describe a very different calculation. For a precise estimate, use the lender’s disclosed APR and amount financed rather than a preliminary figure.

This formula applies to a conventional amortizing loan with a fixed rate and equal monthly payments. It does not model a variable rate, a balloon payment, skipped payments, payment holidays, late charges, or extra principal payments. It also does not decide whether a quoted APR includes particular charges; use the lender’s documents to understand what its quoted figures represent. If the contract has a nonstandard payment schedule, this simple formula may not reproduce its schedule.

Frequently Asked Questions

How do I calculate the total cost of a car loan?
Calculate the monthly payment from the amount financed, APR, and term; multiply the rounded payment by the number of payments to get the estimated total paid. Subtract principal to estimate interest.

Does total car loan cost include the down payment?
No. This calculator totals loan payments only. Add the down payment separately if you are calculating the amount paid toward the vehicle overall, and account separately for other costs paid outside the loan.

Does the calculator include taxes and fees?
Not as separate inputs. If those costs are included in the amount financed, they affect the payment indirectly; otherwise, they are excluded from the result.

Why is my lender’s payment slightly different?
The lender may use different rounding, payment dates, financed charges, or contract terms. Compare the calculator’s assumptions with the disclosure and payment schedule.

Does a longer car loan mean lower total cost?
Not necessarily. It usually means more payments over a longer period; the monthly amount may fall, while total interest can rise. Compare total payments as well as monthly payments.

This result is an estimate, and the lender’s disclosure gives the exact figures.

Related

• Car Loan Rate Calculator Payment and Total Interest
• Car Loan Total Calculator: Payment, Interest and Cost
• Car Loan Prepayment Calculator: Estimate Your Savings

in p | Loan amount | $ | 20000 | 1 | 100000000
in apr | Interest rate (APR) | % | 8 | 0.01 | 100
in yrs | Loan term | years | 5 | 0.0833 | 50
out pmt | Monthly payment | $ | round(p * (apr / 1200) / (1 - (1 + apr / 1200) ^ -(yrs * 12)), 2) | 2
out tot | Total of payments | $ | pmt * yrs * 12 | 2
out int | Total interest | $ | tot - p | 2