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Car Loan Payoff Calculator

See how extra monthly principal shortens your auto loan, how much interest you save, and your estimated payoff month. Includes a simple payoff-today estimate with per-diem interest.

What this calculator is for

An auto loan early payoff calculator shows how extra principal each month shortens the loan and how much interest you avoid. That matters when you get a bonus, sell a project car, or want to free payment room before trading.

Use it at the kitchen table when the lender’s app only shows the next due date, not “what if I add $100?” Shop owners and fleet buyers use the same math for simple payoff today estimates with per-diem interest between your last payment and a payoff quote date.

A good outcome: you know months saved, interest saved, and whether the extra payment beats other uses of cash (high-APR cards, no-match 401k, etc.). Always confirm payoff with your lender — prepayment penalties and deferred interest exist on some subprime paper.

Calculator

How to use this calculator

  1. Extra payments: enter current balance, APR, your lender’s scheduled payment, and any extra principal per month.
  2. Compare months remaining and total interest with vs. without the extra amount.
  3. Payoff today: adds simple per-diem interest since your last payment — confirm with your lender’s payoff quote.

Enter the current principal balance from your statement, not the original loan amount. Use the lender’s required monthly payment unless you are modeling a new plan.

Extra payments only help if they apply to principal immediately. Some lenders hold extras in suspense — call and specify principal reduction.

Payoff-today mode uses simple daily interest; your lender may use different day-count or fees. Treat it as a ballpark before you wire money.

The math: do it without a calculator

Monthly interest = Balance × (APR ÷ 12 ÷ 100)

Principal = Scheduled payment − Interest + Extra

Per-diem ≈ Balance × APR ÷ 365 × days

Each month: interest = balance × (APR ÷ 12 ÷ 100); principal = scheduled payment − interest + extra. Loop until balance ≤ 0.

Per-diem payoff ≈ balance + (balance × APR ÷ 365 × days since last payment). Does not include late fees or NSF charges.

Real-world examples

$100 extra on a used SUV loan

Balance $18,400, 8.1% APR, scheduled payment $382, adding $100/month principal often saves 14–18 months and roughly $2,000+ interest versus minimum payments — exact numbers depend on your lender’s rounding.

Tax refund lump sum

A one-time $2,500 principal payment on the same loan (entered as extra for one month or averaged) cuts life-of-loan interest more than spreading $100/month if you need the loan gone before trading — compare both patterns in the tool.

Troubleshooting & fine-tuning your setup

Payoff Quote Different From the Calculator

Lenders add per-diem interest to today’s payoff and may include fees. The calculator’s payoff-today mode is approximate — call the lender for the wire amount.

Extra payments only work when applied to principal. If months saved look too good, confirm the lender is not advancing your due date without reducing principal.

Frequently asked questions

Early Payoff & Extra Payment FAQs

Is it better to make one lump sum or monthly extra principal?

Earlier principal reduction saves more interest. A lump sum early beats the same total spread late in the loan.

Do extra payments reduce my required monthly payment?

Usually no — they shorten the term unless you request recasting (not all auto lenders offer it).

Are there penalties for paying off a car loan early?

Most auto loans are simple interest without prepayment penalty — read your contract for rare prepayment fee language.

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