Car Payment Schedule Calculator and Loan Basics

A car payment schedule shows each loan payment, how much goes to principal and interest, and the balance left afterward. Enter the amount financed, APR, and term to estimate the monthly payment and total interest; this calculator assumes equal monthly payments at a fixed rate.

Formula

The calculator uses the standard level-payment loan formula. It finds a fixed monthly payment that pays down the balance over the selected number of months, with interest charged on the remaining balance.

• Monthly payment: M = P × r ÷ [1 − (1 + r)⁻ⁿ]
• Total interest estimate: I = M × n − P
• Monthly rate: r = APR ÷ 1,200
• Number of payments: n = loan term in years × 12

P is the amount financed in dollars, APR is the annual percentage rate in percent, r is the monthly rate as a decimal, n is the number of monthly payments, M is the monthly payment in dollars, and I is total interest in dollars. The payment is displayed to the nearest cent. Total interest uses that displayed, rounded payment multiplied by the number of payments, less the original principal; actual lender schedules can differ slightly due to rounding and payment dates.

Worked Example

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

1. Convert the APR to a monthly decimal rate: r = 8 ÷ 1,200 = 0.0066667.
2. Convert the term to months: n = 5 × 12 = 60.
3. Substitute into the payment formula: M = 20,000 × 0.0066667 ÷ [1 − (1.0066667)⁻⁶⁰].
4. The monthly payment is approximately $405.53 after rounding to cents.
5. Total interest estimate = $405.53 × 60 − $20,000 = $4,331.80.

Assumptions

• The APR and payment amount remain fixed for the full term.
• Payments are equal and made monthly; the model does not shift payments for weekends or holidays.
• Interest is modelled monthly at APR divided by 12.
• Fees, taxes, insurance, optional products, and other charges are not included unless they are part of the amount financed you enter.

What a Car Payment Schedule Shows

A full amortization schedule lists the payment number or date, the amount paid, the interest portion, the principal portion, and the remaining balance. Early in a fully amortizing loan, a larger share of each fixed payment generally goes toward interest because the balance is higher. As the balance falls, the interest portion declines and more of the payment reduces principal.

For example, the first month’s estimated interest in the default example is about $133.33: $20,000 × 0.0066667. The rest of the $405.53 payment, about $272.20, reduces principal. The next month’s interest is calculated on the smaller balance, not on the original $20,000. This is why a payment schedule is more informative than multiplying the loan amount by the APR.

This page calculates the regular payment and total interest, not every dated row of the schedule. To construct a row-by-row estimate, start with the opening balance, calculate interest as opening balance × monthly rate, subtract that interest from the payment to get principal repaid, and subtract principal repaid from the opening balance. Repeat for each month. The final payment may need adjustment for rounding.

Choosing Inputs and Reading the Estimate

Use the amount actually financed, rather than assuming it is the vehicle’s sticker price. A down payment or trade-in value can reduce the amount borrowed, while items rolled into financing can increase it. The APR and term should come from the written loan offer or lender disclosure; the default values are only an example and do not represent a current rate or quote.

• Loan amount: Enter the principal being financed. If the final amount is not known, use a clearly identified estimate and recalculate when you have the contract figures.
• APR: Enter the annual percentage rate as a percent, so 8% is entered as 8, not 0.08. Do not enter a monthly rate here.
• Term: Enter the duration in years. The formula converts years into monthly payments.

The result is a scheduled payment under the assumptions above, not a complete measure of vehicle ownership costs. Fuel, maintenance, registration, insurance, and other costs are outside this loan calculation. A longer term spreads repayment across more months and can lower the scheduled payment while increasing the number of months interest accrues. The exact change depends on the amount, APR, and term entered; compare estimates using the same principal and APR if you want to isolate the effect of changing term.

Why a Lender’s Schedule May Differ

A lender may calculate interest using actual payment dates or a daily accrual method, and payment timing can make the result differ from a simple monthly model. The contract may also include fees or financed add-ons, or specify a different first-payment date. Even when the same standard formula applies, rounding each month’s interest to cents can produce a small difference in the final balance or last payment.

Extra payments can also change a schedule, but this calculator does not model them. Depending on the contract and how a payment is applied, extra money may reduce principal, affect later payments, or be handled another way. Check the loan documents or ask the servicer how additional amounts are applied before treating an estimate as a payoff schedule. A payoff quote can include accrued interest through a specific date and other contract details that this calculator does not know.

Common Questions About Car Payment Schedules

How do I calculate a monthly car payment?

Use the amount financed, monthly interest rate (APR divided by 1,200), and total number of monthly payments in the level-payment formula shown above. This calculator performs that calculation and rounds the payment to cents.

Does a car payment include insurance and taxes?

Not necessarily. The result covers principal and interest on the amount entered. Some costs may be included in a financed amount if the loan documents say so, but ongoing insurance and other ownership expenses are not calculated here.

Why does more of my early payment go to interest?

Monthly interest is based on the outstanding principal. The balance is largest at the beginning, so the interest charge takes a larger share of the fixed payment. As principal is repaid, the interest portion generally shrinks.

Can I use this calculator for a lease?

No. A lease payment is not calculated as a standard fully amortizing loan payment; it can depend on lease-specific inputs such as residual value and other charges. Use the lease figures in the relevant contract or a calculator designed for leases.

Why is my lender’s payment different?

The financed amount, APR, term, payment dates, fees, and rounding method may differ from your inputs or from this simplified monthly model. Check the lender’s disclosure for the contractual payment and schedule.

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

Related

• QuickBooks Loan Amortization Schedule Calculator
• Personal Loan Amortization Calculator and Formula
• Quarterly Loan Amortization Calculator and Formula

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