Direct Answer
A car loan amortization calculator with extra payments shows how added principal shortens payoff and cuts interest. Example: $28,000 at 6.9% for 60 months is about $553/month; add $150/month and you finish in roughly 46 months and save about $1,300 in interest. Run your numbers in the Auto Loan Amortization Calculator or Auto Loan Early Payoff Calculator.
Last verified on: July 13, 2026
Editorial note: Examples assume fixed annual percentage rate (APR), extras applied to principal, and no prepayment penalty. Dealer fees and taxes are excluded unless financed into the loan principal.
Research method: Standard amortization with optional extra principal each month. Verified July 13, 2026.
Formula (base payment + extras)
Base payment M = P * [r(1 + r)^n] / [(1 + r)^n - 1]Each month:
- Interest = balance * (APR ÷ 12)
- Principal = min(balance, M + extra - interest)
- New balance = balance - principal
For schedule basics without extras, see car loan amortization schedule explained.
Three worked examples (different cars, rates, terms)
Example 1 - Midsize loan, moderate extras: $28,000 at 6.9% for 60 months
Swipe to see all columns →
| Strategy | Monthly total | Payoff | Total interest | Interest saved |
|---|---|---|---|---|
| Minimum only | $553 | 60 mo | ~$5,187 | - |
| + $75/mo | $628 | ~52 mo | ~$4,444 | ~$743 |
| + $150/mo | $703 | ~46 mo | ~$3,890 | ~$1,297 |
Variation insight: Doubling the extra from $75 to $150 does not double the months saved, but it still removes another ~6 months and ~$550 more interest. Early consistency beats occasional large payments you skip.
Example 2 - Longer term, higher rate: $35,000 at 8.5% for 84 months
Longer terms lower the payment but raise lifetime interest - extras matter more here.
Swipe to see all columns →
| Strategy | Monthly total | Payoff | Total interest | Interest saved |
|---|---|---|---|---|
| Minimum only | $554 | 84 mo | ~$11,559 | - |
| + $100/mo | $654 | ~68 mo | ~$9,150 | ~$2,409 |
Variation insight: Payment is almost the same as Example 1’s minimum (~$554), but you borrow more for longer at a higher APR, so interest more than doubles. $100/month extra recovers over $2,400 - stronger ROI than the same extra on a short, cheaper loan.
Example 3 - Short cheap loan: $18,000 at 5.9% for 36 months
Swipe to see all columns →
| Strategy | Monthly total | Payoff | Total interest | Interest saved |
|---|---|---|---|---|
| Minimum only | $547 | 36 mo | ~$1,684 | - |
| + $50/mo | $597 | ~33 mo | ~$1,531 | ~$153 |
Variation insight: When the rate is low and the term is already short, extras save less interest in dollars. You may prefer parking that $50 toward an emergency fund or higher-APR debt - see should you pay off a car loan early?.
How to run this in Daily Calcs
- Open the Auto Loan Amortization Calculator.
- Enter vehicle price, down payment (or amount financed), APR, and term.
- Add an extra monthly payment and compare payoff date vs interest.
- For a dedicated early-payoff view, use the Auto Loan Early Payoff Calculator.
- Export the schedule if you want a month-by-month checklist.
Practical rules of thumb
- Tell the servicer: apply extras to principal, not “paid ahead.”
- Prioritize extras when APR ≥ your realistic savings/investment return after tax.
- Avoid stretching to 72-84 months just to lower the payment if you will not prepay - Example 2 shows the interest trap.
- Keep insurance and maintenance reserves; do not empty cash for a tiny interest save like Example 3.
Related Reading
- Car loan amortization schedule explained - full table walkthrough
- Should you pay off a car loan early? - when not to prepay
- Extra payments amortization schedule - works for any installment loan
- Personal & business loan amortization - non-auto schedules
- Boat & RV loan amortization
Official and supporting sources
Frequently Asked Questions
How do extra payments affect a car loan amortization schedule?
Extra principal payments reduce the balance immediately, so the next month’s interest is calculated on a smaller amount. The required payment usually stays the same unless you formally refinance or recast. You reach a zero balance sooner and pay less total interest. On a $28,000 loan at 6.9% for 60 months, adding $150/month can cut the term by about 14 months and save roughly $1,300 in interest.
Should I make extra payments monthly or as lump sums?
Monthly extras create a steady reduction in interest. Lump sums help most when applied early, while the balance is highest. A hybrid works well: round every payment up by a fixed amount and add tax-refund or bonus dollars when available. Confirm the lender applies extras to principal, not to future due dates.
Is paying off a car loan early always smart?
Not always. If your APR is low and you have high-interest credit card debt, avalanche the cards first. If the auto APR is mid-to-high single digits or higher, extra principal often beats leaving cash idle. Also check for prepayment penalties (uncommon on many auto notes, but not impossible) and whether you need the liquidity for an emergency fund.
Can I use a car loan amortization calculator with extra payments online?
Yes. Enter amount, APR, and term in the Auto Loan Amortization Calculator, then add an extra monthly principal amount to rebuild the schedule. For a focused payoff comparison, use the Auto Loan Early Payoff Calculator. Export the table to CSV if you want to track progress in a spreadsheet.
Do extra payments change my required monthly payment?
Usually no. You still owe the contractual installment; extras are voluntary amounts on top. Some lenders let you re-amortize after a large lump sum, which can lower the required payment - that is a separate request, similar in spirit to a mortgage recast. Until then, keep paying at least the minimum on time.
What is the formula behind the schedule?
The base payment is M = P × r(1+r)^n / ((1+r)^n − 1), where P is the amount financed, r is APR÷12, and n is the number of months. Each month, interest = balance × r and principal = (M + extra) − interest, capped at the remaining balance. That is the same math used for mortgages, only with shorter auto terms.
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Auto Loan Amortization Calculator
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Auto Loan Early Payoff Calculator
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