Car Amortization Table: Calculate Payments and Balance

A car amortization table shows how each scheduled loan payment is divided between interest and principal, and how the balance declines over time. Enter the amount financed, annual percentage rate (APR), and term below to estimate the monthly payment and total interest; the results do not include vehicle taxes, insurance, or other charges.

Formula

For a fixed-rate loan with equal monthly payments, the payment is calculated using the standard amortizing-loan formula:

Payment = P × r ÷ [1 − (1 + r)⁻ⁿ]

• P is the amount financed, in dollars.
• r is the monthly interest rate as a decimal: APR ÷ 1,200. For an 8% APR, r = 0.08 ÷ 12.
• n is the number of monthly payments: loan term in years × 12.

The calculator rounds the monthly payment to the nearest cent. Its total-interest estimate is rounded monthly payment × number of payments − amount financed. Because real lenders may adjust the final payment or use different payment dates and rounding, their disclosed figures can differ slightly.

Worked Example

Using the calculator’s default inputs—$20,000 financed, 8% APR, and five years:

1. Convert the APR to a monthly decimal rate: 8 ÷ 1,200 = 0.0066667.
2. Find the number of payments: 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 the rounded payment: $405.53 × 60 − $20,000 = $4,331.80.

The estimate is therefore a monthly payment of $405.53 and total interest of $4,331.80 across 60 payments.

Assumptions

• The interest rate stays fixed for the entire term.
• Payments are equal, made monthly, and paid at the end of each monthly period.
• Interest is modelled monthly using APR ÷ 12.
• The calculation excludes fees, taxes, insurance, add-ons, and any other amount not included in the loan amount.

How to Read a Car Amortization Table

A full amortization table has one row for each payment. Common columns show the payment number or date, starting balance, scheduled payment, interest charged, principal repaid, and ending balance. For a standard fixed-rate loan, the scheduled payment remains level, but its split changes as the balance falls.

For each row, interest is generally calculated on the balance outstanding at the start of that period. The principal portion is the payment minus that period’s interest. Subtracting principal from the starting balance gives the new balance. In early payments, more of the payment usually goes to interest because the outstanding amount is larger; later, a greater share goes to principal.

This calculator reports the payment and total interest, not every row of the schedule. To build a table, repeat the row calculations for each month using the lender’s payment dates, interest method, and rounding conventions. The final row should bring the balance close to zero, though exact lender calculations can leave a small difference for the final payment.

What Amount Should You Enter?

Enter the amount actually financed, not automatically the vehicle’s advertised price. The financed amount may differ after a down payment, trade-in credit, taxes, fees, or optional items are accounted for. Those details depend on the transaction and the loan documents, so use the amount shown by the lender when available.

• Loan amount: Use the principal being borrowed. If you are only estimating, clearly distinguish the vehicle price from the amount financed.
• APR: Enter the annual percentage rate supplied for the specific loan offer. Do not substitute a market average or confuse an interest rate with a quoted APR.
• Term: Enter the repayment length in years. The calculator converts it to months; a term of five years means 60 scheduled monthly payments.

The default values are only an example for demonstrating the formula. They do not represent a current rate, a lender offer, or an assessment of whether a payment fits someone’s budget.

What Changes the Payment and Total Cost?

With the other inputs held constant, a larger amount financed increases the payment. A higher APR also increases the payment and the total interest. A longer term generally reduces the scheduled monthly payment, but it also means more payment periods; with the same principal and APR, total interest is generally higher. These are mathematical effects of the formula, not a recommendation about what term or loan to choose.

Extra payments can affect the real schedule, but this calculator assumes the stated regular payment throughout and does not model extra principal, skipped or late payments, refinancing, or a changing rate. Ask the lender how additional amounts are applied and whether its payoff balance includes interest accrued since the last payment.

Common Problems and Limits

A frequent mistake is using the vehicle’s price rather than the amount financed, or entering 8 instead of 0.08 into a formula that expects a decimal rate. Here, enter APR as a percentage—8 means 8%—and the formula converts it to a monthly decimal by dividing by 1,200. The term input is in years, not months.

Another misconception is that total interest equals the difference between the car’s price and what is paid over the loan. The calculator compares total scheduled payments with the amount financed; it does not account for a down payment, trade-in, fees, insurance, or the vehicle’s future value. It also does not calculate an official payoff amount or an itemized lender statement.

The formula is for a fully amortizing loan with fixed APR, equal monthly payments, and ordinary monthly periods. It may not match a contract with a variable rate, irregular payment dates, a balloon payment, deferred interest, or a different interest-accrual method. For exact figures, use the lender’s loan disclosure and payment schedule.

Frequently Asked Questions

What does a car amortization table show?
It shows how each scheduled payment is divided between interest and principal, plus the remaining balance after the payment.

Does this calculator create a month-by-month table?
No. It estimates the monthly payment and total interest. A detailed schedule requires calculating the interest and principal portions for each payment period.

Why does the interest portion usually decrease?
With a fixed rate, each period’s interest is based on the outstanding balance. As principal is repaid and the balance falls, the interest charged per period generally falls too.

Is APR the same as the monthly interest rate?
No. APR is entered as a yearly percentage. This estimate converts it to a monthly rate by dividing by 12 and converting percent to decimal, or APR ÷ 1,200.

Why might the lender’s payment differ by a few cents?
Lenders may use different payment dates, accrual conventions, rounding rules, or include amounts not entered here. Compare the calculator’s assumptions with the loan disclosure.

Can I use this to find an exact payoff balance?
No. The estimate does not account for the precise date of payoff, accrued interest since the last payment, or contract-specific charges. Request a payoff figure from the lender.

This result is an estimate for education; 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 | $ | round(p * (apr / 1200) / (1 - (1 + apr / 1200) ^ -(yrs * 12)), 2) | 2
out int | Total interest | $ | pmt * yrs * 12 - p | 2