calculate-loan

01 Loan payments

Car Loan Payment Calculator: Estimate Your Monthly Cost

Calculator No. 01-6868 · Updated · Formula and assumptions shown below

Monthly payment $405.53
Total interest
$4,331.67
= Monthly payment × loan term × 12 − loan amount
Loan amount
$20,000
Input
Interest rate (APR)
8 %
Input
You enter
Loan amount ($), Interest rate (APR) (%), Loan term (years)
You get
Monthly payment ($), Total interest ($)
Rounding
2 dp

Estimate for education, not financial advice. The result follows from the numbers you enter and the formula shown. It is not a quote or an offer, and it does not include fees, taxes or insurance unless the calculator asks for them. Ask your lender for the exact figures.

This car loan calculator estimates your monthly payment and total interest from the amount financed, APR, and loan term. Enter those three figures to see the scheduled payment and the interest implied by the rounded monthly payment.

Formula

The calculator uses the standard fixed-payment loan formula. It first finds the payment from the principal, monthly interest rate, and number of monthly payments:

Monthly payment = P × r ÷ [1 − (1 + r)−n]

  • P is the loan amount, in dollars.
  • r is the monthly interest rate as a decimal: APR ÷ 1200. For an 8% APR, r = 8 ÷ 1200.
  • n is the number of monthly payments: years × 12.

Total interest is estimated as monthly payment × n − P. The displayed payment is rounded to the nearest cent; total interest uses that rounded payment. The formula assumes equal monthly payments and a fixed rate throughout the term.

Worked Example

Using the calculator’s defaults—$20,000 financed, 8% APR, and 5 years:

  1. Convert the APR to a monthly decimal rate: 8 ÷ 1200 = 0.0066667.
  2. Convert the term to payments: 5 × 12 = 60 months.
  3. Substitute into the formula: $20,000 × 0.0066667 ÷ [1 − (1.0066667)−60] = about $405.53 per month, rounded to cents.
  4. Calculate total interest using the rounded payment: $405.53 × 60 − $20,000 = $4,331.80.

For these inputs, the estimated monthly payment is $405.53, and estimated total interest is $4,331.80. A lender’s payment schedule can differ because of rounding conventions, fees, payment dates, or other loan terms.

Assumptions

  • The APR is fixed for the entire loan term.
  • Payments are equal, monthly, and made at the end of each monthly period.
  • Interest accrues monthly using APR divided by 12.
  • The calculation excludes fees, taxes, insurance, optional products, and any down payment except insofar as they affect the amount entered as the loan amount. It does not model a changing balance or extra payments.

What Changes a Car Loan Payment?

The payment is driven mainly by the amount borrowed, the APR, and the number of payments. A larger principal generally raises the payment; a higher APR raises both the payment and the interest cost. A longer term spreads repayment across more months, which usually lowers the scheduled monthly amount but can increase total interest because interest accrues for longer.

The loan amount is not necessarily the vehicle’s advertised price. A down payment or trade-in value can reduce the amount financed, while taxes, fees, or add-ons included in the contract can increase it. For an estimate that resembles a loan quote, use the amount the lender says will actually be financed, not just the sticker price.

APR is an annualized rate used to express borrowing cost. This calculator treats the APR as a fixed nominal annual rate and divides it by 12 for monthly calculations. It does not determine an APR from a vehicle price or predict what rate a lender may offer. Use the rate and financed amount in the lender’s written terms.

How to Read the Estimate

The monthly payment is the scheduled principal-and-interest amount under the formula, not necessarily the full cost of owning or operating a vehicle. Insurance, fuel, maintenance, registration, and other ownership expenses are outside the calculation. A contract may also include charges or payment timing that this basic model does not represent.

Total interest is the estimated amount paid above the original principal over the full scheduled term. It is not the total of all payments: adding the loan amount to the displayed interest gives the scheduled total paid toward principal and interest. Because the displayed payment is rounded to cents before multiplying by the number of months, the result can differ slightly from a total computed with an unrounded payment.

Common Mistakes and Limits

  • Entering the vehicle price instead of the amount financed: subtract any down payment or trade-in credit that is actually applied, and include only amounts that become part of the loan balance.
  • Mixing annual and monthly rates: enter APR as a percentage per year, such as 8, not 0.08 or a monthly rate. The calculator converts it to a monthly decimal.
  • Confusing term length with years of payments: the input is years; the formula multiplies it by 12. A five-year term means 60 monthly payments.
  • Assuming the estimate is a payoff quote: actual payoff amounts can reflect accrued interest, payment dates, fees, or contract-specific calculations.

The formula is for a conventional fixed-rate loan with level monthly payments. It does not model a balloon payment, a variable rate, skipped or late payments, extra principal payments, or a contract with a different payment schedule. For an exact amount, compare the calculator’s assumptions with the loan disclosure and payment schedule.

Frequently Asked Questions

How much is a monthly payment on a $20,000 car loan?
It depends on APR and term. With the calculator’s example of 8% APR over five years, the estimated payment is $405.53 a month, excluding costs not included in the loan formula.

Does a longer car loan lower the monthly payment?
For the same principal and APR, spreading repayment over more months generally lowers each scheduled payment. It can also raise total interest because the balance is repaid over a longer period.

Does this payment include taxes and insurance?
No. The calculator estimates principal and interest only. Taxes or fees affect the result only if included in the loan amount you enter; insurance and other vehicle expenses are not calculated.

Why does my lender’s payment differ from this estimate?
The contract may use a different financed amount, APR, term, payment date, fee treatment, or rounding method. Check the lender’s payment schedule and disclosure for the contract-specific figures.

Is APR entered as a monthly or yearly rate?
Enter the annual percentage rate as a yearly percentage. The calculator divides it by 12 and converts it to a decimal for the monthly payment formula.

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

Related

Formula used
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

Each line is one input (in, sel, list) or one result (out: label, unit, formula, decimals). How the calculators work

Method: the standard loan formula for this calculation, fixed rate and monthly compounding unless stated, rounded as each result states. Not financial advice; no lender, rate or product is recommended. See formulas and assumptions, the disclaimer or report an error.

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