Car Loan Calculator
Calculate a car loan payment from price, APR, term, trade equity, tax, fees, and extra principal with payoff and cost warnings.Monthly Payment
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Introduction:
Car financing turns a vehicle price into a repayment schedule. The price on the window sticker is only one part of that schedule. Down payment, rebate, trade equity, sales tax, flat fees, and any remaining loan on the old vehicle all change the amount that becomes principal before interest is added.
The monthly payment is the number most buyers notice first, but it is not the whole cost of the deal. A longer term can make the bill look easier to handle while adding months of interest and slowing the path to positive equity. A smaller down payment can protect cash today while leaving a larger balance exposed to depreciation. Financing taxes, title fees, dealer fees, or old loan debt means those costs are no longer one-time charges; they become interest-bearing principal.
Several terms make loan comparisons easier. The annual percentage rate (APR) is the yearly credit-cost measure used to compare offers. Principal is the balance being repaid. Interest is the finance cost caused by carrying that balance. Amortization is the monthly process in which each payment first covers interest for the period, then reduces principal.
| Choice | Usual effect | What to check |
|---|---|---|
| Higher down payment | Reduces principal | Confirm enough cash remains for insurance, registration, repairs, and emergencies. |
| Longer loan term | Reduces payment, extends interest time | Compare total interest and the payoff month, not only the bill due each month. |
| Trade-in with payoff | Can create positive or negative equity | Subtract the old loan payoff from the trade allowance before treating it as a credit. |
| Financed tax and fees | Moves upfront costs into the loan | Look for interest charged on costs that could have been paid at signing. |
A loan estimate is strongest when it compares offers with the same assumptions. It cannot tell whether the dealer contract is fair, whether the lender will approve the credit application, or whether the vehicle is affordable after fuel, maintenance, repairs, registration, insurance, and depreciation are included.
How to Use This Tool:
Start with the price or quote, then add the parts of the deal that change the amount financed. Use the same assumptions for every offer you compare.
- Enter Vehicle price or financed amount, Interest rate, and Loan term. The term uses whole years plus 0 to 11 extra months, so a 72-month quote is 6 years and 0 months.
- Open Advanced when the deal includes a Down payment, Trade-in value, Trade-in loan payoff, Rebate or incentive, Sales tax rate, or Title and dealer fees.
- Choose whether the down payment is a dollar amount or a percent. Percent entries are capped at 100%, and dollar entries cannot exceed the vehicle amount.
- Set Trade-in reduces tax base only when your local tax rules allow the trade value to reduce the taxable amount.
- Use Finance tax and fees to decide whether tax and flat fees become part of Amount financed ($) or stay in Cash due at signing ($).
- Keep Interest method on Monthly compounding (standard) for ordinary quote comparisons. The simple-daily option resolves to the same monthly APR conversion, while continuous compounding uses a slightly different rate conversion.
- Enter Extra monthly payment when you want to test faster payoff, then compare Extra Payment Comparison, Annual Paydown Schedule, and Balance Paydown Chart.
- Review warnings before relying on the schedule. Fix invalid amounts or terms, and pay special attention to negative equity, terms above 84 months, or credits that cover the whole deal.
Interpreting Results:
Monthly payment ($) shows the scheduled base payment plus any extra monthly principal. Read it beside Amount financed ($), Total interest ($), Total cost ($), and Actual payoff (months) before deciding that a lower payment is a better deal.
- Cash due at signing ($) separates upfront cash from costs rolled into the loan. A low cash-due number can still be expensive if taxes, fees, or old debt are financed.
- Trade-in effect shows positive equity as a credit or negative equity as old debt added to the new note.
- Finance charge share (%) compares interest with the financed amount. A high share usually points to a large balance, high APR, long term, or too little extra principal.
- Annual Paydown Schedule is useful for seeing when principal begins to dominate each year's payments.
- Finish (local) is an estimate based on the computed payoff months. Actual payoff dates can change with payment timing, lender posting rules, late fees, skipped payments, or prepayment restrictions.
Technical Details:
Fixed-rate auto financing starts by translating the purchase terms into principal. Credits such as down payment, rebate, and positive trade equity reduce principal. Negative equity and financed taxes or fees increase principal. Once the principal is known, the repayment schedule applies a monthly rate to the remaining balance and uses the rest of the payment to reduce that balance.
Amortization is interest-heavy at the beginning because the unpaid balance is largest then. The scheduled payment stays stable in a fixed-rate model, but the interest share falls as principal is paid down. Extra monthly principal shortens the schedule because it lowers the balance before later interest charges are computed.
Formula Core:
The balance equation combines deal credits and costs before the fixed-payment equation is applied. If APR is zero, the base payment is simply principal divided by the number of months.
Q is Amount financed ($), P is the vehicle amount, B is rebate applied, D is down payment applied, E is positive trade equity, N is negative equity, C is financed tax and fees, j is the effective monthly rate, n is the original term in months, and M is the base payment before extra principal.
For example, a $30,345 financed balance at 5.9% APR over 72 months uses a monthly rate of 0.059 / 12. The base payment is about $501.47, total interest is about $5,761, and total loan cost is about $36,106 before insurance, registration, maintenance, or ownership costs outside the note.
| Rule | Applied behavior | Effect |
|---|---|---|
| Down payment cap | Dollar down payment cannot exceed the vehicle amount; percent down payment cannot exceed 100% | Credits cannot create a negative financed balance. |
| Rebate cap | Rebate is capped at the vehicle amount | The tax and balance calculations do not subtract more rebate than the entered price. |
| Trade-in equity | Trade value above payoff becomes positive equity; payoff above trade value becomes negative equity | Positive equity lowers principal, while negative equity raises it. |
| Trade-in tax credit | When enabled, taxable value is reduced by trade value, capped at the vehicle amount | Sales tax falls only when the selected tax-credit assumption applies. |
| Interest method | Standard and simple-daily convert to APR / 12; continuous uses an exponential monthly conversion | The continuous option can shift the payment slightly for the same APR. |
| Schedule limit | Rows stop when the balance reaches zero, with a 1200-month safety cap | The final row may be smaller than the regular payment because it is capped at the remaining balance. |
Dollar amounts are rounded for display after the schedule is calculated. Lender schedules can differ by cents or by payoff date when they use different rounding rules, first-payment timing, daily interest posting, payment holidays, late fees, or prepayment rules.
Responsible Use Note:
This is an educational planning estimate, not financial advice, a credit approval, or a binding disclosure. It does not check credit, submit an application, contact a lender, or verify state and local tax rules.
- Compare offers by APR, interest rate, amount financed, term, payment, finance charge, and total cost.
- Read the Truth-in-Lending disclosure and retail installment contract before signing.
- Ask how extra payments are applied and whether any prepayment penalty, add-on product, dealer fee, or rolled-in warranty changes the true cost.
- Estimate insurance, registration, maintenance, fuel, repairs, and depreciation separately because they are not included in the payment schedule.
Worked Examples:
Purchase with trade equity:
A $36,500 vehicle with $4,500 down, a $1,500 rebate, a $9,000 trade worth $6,500 after payoff, 6.25% sales tax, and $720 in fees finances about $30,345 when tax and fees are rolled into the loan. At 5.9% APR for 72 months, the base payment is about $501.47 and total interest is about $5,761.
Negative equity on a long term:
A trade worth $10,000 with $14,500 still owed adds $4,500 of old debt to the new note. On a 96-month term, the warnings call out both negative equity and the term above 84 months, so Total interest ($) and Actual payoff (months) deserve more attention than the lower payment.
Extra principal test:
A $26,298.75 financed balance at 6.2% APR for 60 months has a base payment of about $510.88. Adding $125 in Extra monthly payment raises the monthly outflow to about $635.88, trims the payoff path to about 47 months in the model, and saves roughly $990 in interest compared with the same setup without extra principal.
Credits cover the deal:
If a $25,000 vehicle is offset by a $25,000 down payment and no financed tax or fees, there is no principal to amortize. The warning explains that payment rows return only after Amount financed ($) is positive and the term is at least one month.
FAQ:
Why is the amount financed different from the vehicle price?
The amount financed starts with the vehicle amount, subtracts down payment, rebate, and positive trade equity, adds negative equity, and includes tax and fees when those costs are financed.
Why can a longer term cost more if the monthly payment is lower?
A longer term spreads principal across more months, so the scheduled payment falls, but interest has more time to accrue on the remaining balance.
What does negative equity mean here?
Negative equity appears when the trade-in loan payoff is higher than the trade-in value. The difference is added to the new loan balance and can keep the borrower owing more than the new vehicle is worth for longer.
Why do the standard and simple-daily methods match?
Both methods convert APR to a monthly rate for this monthly amortization schedule. The simple-daily label is a comparison setting, not a lender-specific daily-interest contract model.
Why did the schedule disappear?
A schedule requires a positive amount financed and a term of at least one month. Reduce credits, enter a positive vehicle amount, or set a valid term to restore the payment rows.
Glossary:
- Amount financed
- The principal balance after credits, tax, fees, and trade-in effects are applied.
- APR
- Annual percentage rate, the yearly credit-cost measure used to compare loan offers.
- Amortization
- The month-by-month process of paying interest and reducing principal.
- Finance charge
- The interest cost estimated across the repayment schedule.
- Negative equity
- Old vehicle debt added to the new loan because trade-in payoff exceeds trade-in value.
- Principal
- The unpaid balance before interest is charged for the period.
- Cash due at signing
- Upfront cash from down payment plus any tax or fees not financed.
References:
- Auto loans key terms, Consumer Financial Protection Bureau.
- How do I compare auto loan offers?, Consumer Financial Protection Bureau, Jan. 30, 2024.
- What is a Truth-in-Lending disclosure for an auto loan?, Consumer Financial Protection Bureau.
- What things can I negotiate when shopping for a car or auto loan?, Consumer Financial Protection Bureau, Aug. 28, 2024.
- Auto Trade-Ins and Negative Equity: When You Owe More than Your Car is Worth, Federal Trade Commission, September 2023.