Car Loan Repayment Schedule Calculator

A car loan repayment schedule shows each monthly payment’s split between principal and interest, along with the remaining balance. Enter the amount financed, APR, and term to estimate the monthly payment and total interest; the schedule itself can then be built from those figures.

Formula

The calculator uses the standard fixed-payment loan formula. Monthly payment = P × r ÷ [1 − (1 + r)⁻ⁿ], where r = APR ÷ 1,200 and n = years × 12. Total interest = (monthly payment × n) − P. In these formulas, P is the amount financed in dollars, APR is the annual percentage rate entered as a percentage, r is the monthly rate as a decimal, and n is the number of monthly payments. The displayed payment is rounded to cents; this formula’s results are estimates and the actual final payment can differ due to lender rounding or payment dates.

Worked Example

Using the calculator’s defaults: amount financed P = $20,000, APR = 8%, and term = 5 years.

1. Convert the annual rate to a monthly decimal: r = 8 ÷ 1,200 = 0.0066667.
2. Convert the term to payments: n = 5 × 12 = 60.
3. Apply the payment formula: $20,000 × 0.0066667 ÷ [1 − (1.0066667)⁻⁶⁰] = $405.53 per month, rounded to cents.
4. Calculate total interest using that rounded payment: ($405.53 × 60) − $20,000 = $4,331.80.

Assumptions

• The interest rate is fixed for the full modeled term.
• Payments are equal, monthly payments made at the end of each monthly period.
• Interest compounds monthly at APR ÷ 12.
• The calculation excludes lender fees, taxes, vehicle insurance, and other charges; these are not inputs to this calculator.

How a Car Loan Repayment Schedule Works

A repayment schedule, also called an amortization schedule, lays out what happens to the balance at each payment. At the beginning, interest is calculated on a relatively large outstanding balance, so more of a level payment goes toward interest. As principal is repaid, the balance falls; later payments therefore contain a larger principal share and a smaller interest share.

For a schedule row, monthly interest is generally the balance before payment multiplied by the monthly rate. Principal paid is the payment minus that interest, and the new balance is the old balance minus principal paid. For example, with the defaults above, first-month interest is approximately $20,000 × 0.0066667 = $133.33. Of the $405.53 payment, approximately $272.20 reduces principal, leaving about $19,727.80. Actual lender schedules can vary slightly with rounding and the timing of payments.

What the Calculator Tells You

The first result is the estimated scheduled monthly payment for the principal and interest represented by the inputs. Total interest is the sum of the scheduled payments minus the amount financed, using the displayed payment rounded to cents. It does not represent the total cost of owning or operating a car.

To estimate the amount financed, distinguish the vehicle’s price from the loan principal. A down payment or trade-in can reduce the amount borrowed, while amounts added to financing can increase it. The lender’s loan documents determine which items are included in the actual principal. Enter that financed amount—not automatically the sticker price—in the calculator.

Using a Full Payment Schedule

For a month-by-month estimate, repeat the interest and balance calculations for each payment. A table can use these columns:

• Payment number and scheduled payment date
• Starting balance
• Interest charged for the period
• Principal repaid
• Ending balance

For each row, calculate interest as starting balance × monthly rate, principal as payment − interest, and ending balance as starting balance − principal. The ending balance becomes the next row’s starting balance. Keep extra payments separate from the scheduled payment and apply them according to the lender’s handling; the timing and application can affect the result. On the final row, a small adjustment may be needed because real servicing systems round amounts during the loan rather than carrying unlimited decimals.

Factors That Change the Schedule

The amount financed, APR, and term are the main inputs. Holding the other values constant, a larger principal or higher APR increases the calculated payment. A longer term generally lowers the scheduled payment but can increase total interest because interest accrues for more monthly periods. These are mathematical effects, not a recommendation about which loan structure to select.

The APR is an input, not something this calculator determines. Use the rate and principal shown in the lender’s disclosure for a closer estimate. Fees, payment timing, variable rates, deferred payments, and other contract details can make the real schedule differ. A rate shown as an APR may also reflect costs differently from a simple interest rate; the calculator does not separately model financed fees or daily interest conventions.

Common Misunderstandings and Limits

A monthly payment is not the same as a monthly principal reduction. Early in a standard amortizing loan, part of each payment covers interest, as the worked example shows. Nor is total interest the same as total repayment: total repayment includes the amount borrowed as well as interest.

This calculator assumes a fixed rate and equal monthly periods. It does not model a balloon payment, skipped or late payments, changes in rate, payoff quotes, or the exact effect of an extra payment. A vehicle’s insurance, fuel, maintenance, registration, and taxes are also outside the calculation. For the contractual payment dates, precise payoff amount, or official balance, refer to the lender’s current statement or disclosure.

Frequently Asked Questions

What is included in a car loan repayment schedule?
A typical schedule lists each payment, the interest and principal portions, and the remaining balance. Contract-specific fees or charges may be shown separately.

Why does more of the payment go to interest at first?
Interest is calculated on the outstanding balance. That balance is largest at the start, so the interest portion is larger; as principal falls, the interest portion generally falls too.

Does a longer car loan term reduce total interest?
Not necessarily. With the same principal and APR, extending the term usually reduces the scheduled monthly payment but increases the number of periods over which interest accrues, generally increasing total interest.

Is the calculator’s payment the exact amount a lender will charge?
It is an estimate under the stated assumptions. Lender rounding, payment dates, fees, and the contract’s interest method can change the exact amount.

Can I use the schedule to estimate an early payoff?
It can help illustrate how a balance might decline under regular payments, but it does not calculate an official payoff quote or model every extra-payment rule. Request a current payoff figure from the lender.

The result is an estimate; the lender’s disclosure gives the exact figures.

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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 | $ | p * (apr / 1200) / (1 - (1 + apr / 1200) ^ -(yrs * 12)) | 2
out int | Total interest | $ | pmt * yrs * 12 - p | 2