Car Loan Repayment Calculator: Monthly Payment & Total Cost

Use this car loan repayment calculator to instantly estimate your monthly payment and the total interest you will pay over the life of your auto loan. Simply enter the vehicle price, your down payment, the annual interest rate offered by your lender, and your preferred loan term. The calculator applies the standard amortization formula used by banks and credit unions, giving you a clear picture of your financing costs before you sign anything at the dealership.

How to Use This Calculator

Follow these steps to get an accurate estimate of your auto loan costs:

1. Enter the vehicle price — use the agreed purchase price or the sticker price you are negotiating from.
2. Enter your down payment — the cash you plan to pay upfront. A larger down payment reduces your principal and total interest.
3. Enter your trade-in value — if you are trading in a vehicle, enter the dealer’s offer. Leave at zero if not applicable.
4. Set the annual interest rate (APR) — use the rate quoted by your lender or the best pre-approval offer you have received.
5. Choose your loan term — select the number of months you want to repay the loan over, from 12 to 96 months.
6. Enter your local sales tax rate — this is added to the vehicle price and typically financed into the loan.
7. Enter any fees — include documentation fees, registration, and dealer charges that will be rolled into the loan.
8. Read your results — the calculator instantly shows your monthly payment, total interest, and full out-of-pocket cost.

Understanding the Calculator Inputs

Vehicle Price ($): Enter the full purchase price of the car as agreed with the seller or shown on the window sticker. Do not subtract any discounts you have already negotiated — enter the final agreed price. This is the foundation of every calculation.

Down Payment ($): Enter the cash amount you will pay upfront at signing. A higher down payment directly reduces the amount you need to borrow, which lowers both your monthly payment and the total interest you pay over the life of the loan. Financial advisors commonly suggest putting down at least 10–20% of the vehicle price.

Trade-In Value ($): If you are trading in your current vehicle, enter the value the dealer has offered or the estimated private-sale value you are applying toward the purchase. This amount is subtracted from the financed principal just like a cash down payment. If you owe more on your trade-in than it is worth (negative equity), enter zero here and add the negative equity balance to the Fees field instead.

Annual Interest Rate — APR (%): Use the slider to set the annual percentage rate your lender has quoted or pre-approved. The APR is the yearly cost of borrowing expressed as a percentage. Rates vary widely based on your credit score, loan term, lender type, and whether the vehicle is new or used. As of recent years, new-car rates for well-qualified buyers have ranged from roughly 5% to 8%, while used-car rates are typically 1–4 percentage points higher.

Loan Term (months): Select the number of months over which you will repay the loan. Common terms are 36, 48, 60, 72, and 84 months. Shorter terms mean higher monthly payments but significantly less total interest. Longer terms lower the monthly payment but increase the total cost of the loan and raise the risk of becoming upside-down on the loan (owing more than the car is worth).

Sales Tax Rate (%): Enter your state or local sales tax rate. In most U.S. states, sales tax is calculated on the vehicle purchase price and is typically rolled into the financed amount rather than paid separately at signing. Rates vary by state and sometimes by county or city. If you are unsure of your exact rate, check your state’s department of revenue website.

Fees & Other Charges ($): Include any dealer documentation fees, title fees, registration fees, or other charges that will be financed into the loan rather than paid out of pocket at signing. Common doc fees range from $100 to $800 depending on the state. Do not include fees you plan to pay in cash at closing, as those are not part of the financed amount.

Understanding Your Results

Loan Principal (Amount Financed): This is the net dollar amount you are actually borrowing — the vehicle price plus tax and fees, minus your down payment and trade-in value. This is the balance on which all interest is calculated. Reducing this number through a larger down payment or trade-in has a compounding benefit because every dollar of principal reduction saves you interest for every remaining month of the loan.

Monthly Payment: This is the fixed amount you will owe your lender each month for the duration of the loan term. It is calculated using the standard amortization formula and remains constant throughout the loan (assuming a fixed rate). Use this figure to assess whether the loan fits comfortably within your monthly budget. A common rule of thumb is that total vehicle expenses — payment, insurance, fuel, and maintenance — should not exceed 15–20% of your monthly take-home pay.

Total Amount Paid: This is the sum of all monthly payments over the full loan term. It represents the total cash outflow for the financed portion of the vehicle and does not include the down payment or trade-in value you contributed upfront.

Total Interest Paid: This is the difference between the total amount paid and the original loan principal. It is the true cost of borrowing — the amount you pay the lender above and beyond what you borrowed. Comparing this figure across different loan terms and interest rates is one of the most powerful ways to evaluate financing options.

Total Vehicle Cost (Out-of-Pocket): This adds your down payment and trade-in value back to the total amount paid, giving you the complete all-in cost of the vehicle purchase. This is the most honest representation of what the car actually costs you in total dollars spent.

Interest as % of Principal: This percentage shows how much extra you pay relative to what you borrowed. For example, a result of 20% means you pay $1.20 for every $1.00 borrowed. This metric is useful for quickly comparing the efficiency of different loan offers without needing to calculate dollar amounts.

Calculation Formulas Explained

The calculator uses the standard fixed-rate amortization formula, which is the same method used by banks, credit unions, and auto lenders worldwide.

Step 1 — Loan Principal (P): The principal is calculated as: (Vehicle Price × (1 + Sales Tax Rate / 100)) + Fees − Down Payment − Trade-In Value. Sales tax is applied to the vehicle price first, then fees are added, and then the down payment and trade-in are subtracted.

Step 2 — Monthly Interest Rate (r): The annual interest rate is divided by 12 to get the monthly periodic rate: r = Annual Interest Rate / 100 / 12. For example, a 6.5% APR becomes a monthly rate of approximately 0.5417%.

Step 3 — Monthly Payment (M): The amortization formula is: M = P × [r × (1 + r)^n] / [(1 + r)^n − 1], where n is the number of monthly payments (loan term in months). This formula ensures that each payment covers the interest accrued that month plus a portion of the principal, with the principal portion growing over time.

Step 4 — Total Amount Paid: M × n — the monthly payment multiplied by the number of payments.

Step 5 — Total Interest Paid: Total Amount Paid − Principal — the excess paid above the original loan balance.

Step 6 — Total Out-of-Pocket Cost: Total Amount Paid + Down Payment + Trade-In Value — adds back the upfront contributions to show the complete cost of ownership from a cash-flow perspective.

Step 7 — Interest as % of Principal: (Total Interest Paid / Principal) × 100 — expresses the interest burden as a simple percentage of the amount borrowed.

Worked Example

Scenario: You are buying a used SUV priced at $28,000. You have $4,000 cash for a down payment and a trade-in worth $2,000. Your lender has pre-approved you at 7.0% APR for 60 months. Your state sales tax rate is 6%, and the dealer charges $400 in documentation fees.

1. Calculate taxed vehicle price: $28,000 × (1 + 6/100) = $28,000 × 1.06 = $29,680
2. Add fees: $29,680 + $400 = $30,080
3. Subtract down payment and trade-in: $30,080 − $4,000 − $2,000 = $24,080 principal
4. Calculate monthly rate: 7.0% / 12 = 0.5833% = 0.005833
5. Calculate (1 + r)^n: (1.005833)^60 ≈ 1.41763
6. Calculate monthly payment: $24,080 × (0.005833 × 1.41763) / (1.41763 − 1) = $24,080 × 0.008271 / 0.41763 ≈ $24,080 × 0.019801 ≈ $476.82/month
7. Total amount paid: $476.82 × 60 = $28,609.20
8. Total interest paid: $28,609.20 − $24,080 = $4,529.20
9. Total out-of-pocket cost: $28,609.20 + $4,000 + $2,000 = $34,609.20
10. Interest as % of principal: $4,529.20 / $24,080 × 100 ≈ 18.81%

In this example, financing adds over $4,500 to the cost of the vehicle. Shortening the term to 48 months at the same rate would raise the monthly payment to roughly $577 but reduce total interest to about $3,680 — a saving of nearly $850.

How to Interpret the Results

Is your monthly payment affordable? A widely used guideline is that your total monthly car expenses — loan payment, insurance, fuel, and maintenance — should not exceed 15% to 20% of your monthly net income. If the monthly payment alone approaches that threshold, consider a larger down payment, a longer term as a temporary measure, or a less expensive vehicle.

Is your interest rate competitive? Compare the Interest as % of Principal result across different rate scenarios. A difference of even 1–2 percentage points in APR can add or remove hundreds to thousands of dollars in total interest over a 60- or 72-month term. Always get pre-approved by a bank or credit union before visiting a dealership so you have a benchmark rate to compare against dealer financing offers.

How does loan term affect your decision? Longer loan terms (72–96 months) produce lower monthly payments but dramatically increase total interest paid and create a higher risk of negative equity — owing more than the car is worth — especially in the first two to three years. If the Interest as % of Principal result exceeds 25–30%, consider whether a shorter term or larger down payment would be more financially sound.

Comparing multiple offers: Run the calculator once for each loan offer you receive, keeping all other inputs constant and changing only the APR and term. The Total Interest Paid and Interest as % of Principal results give you a direct, apples-to-apples comparison of the true cost of each offer.

Common Mistakes to Avoid

• Forgetting sales tax and fees: Many buyers focus only on the vehicle price and are surprised when the financed amount is significantly higher. Always include your local tax rate and all fees that will be rolled into the loan to get an accurate payment estimate.
• Choosing the longest term to minimize monthly payments: A 84- or 96-month loan may seem attractive because of the low monthly payment, but the total interest paid can be two to three times higher than a 48-month loan at the same rate. Always check the Total Interest Paid result before committing to a long term.
• Ignoring negative equity on a trade-in: If you owe more on your current vehicle than it is worth, that negative equity is typically rolled into the new loan, increasing your principal. This calculator assumes the trade-in value is positive equity. If you have negative equity, add that amount to the Fees field to capture it in the principal.
• Using the dealer’s monthly payment as the only comparison point: Dealers sometimes extend the loan term to make a higher-priced vehicle appear affordable on a monthly basis. Always compare Total Interest Paid and Total Vehicle Cost, not just the monthly payment.
• Not accounting for GAP insurance and add-ons: Extended warranties, GAP insurance, and other dealer add-ons are often rolled into the loan without buyers realizing it. These increase the principal and the total interest paid. Add them to the Fees field if they will be financed.
• Assuming 0% APR financing is always the best deal: Manufacturers offering 0% APR promotions often require buyers to forgo a cash rebate. Run the numbers both ways — sometimes taking the rebate and financing at a low market rate saves more money overall.

Limitations and Important Notes

This calculator assumes a fixed interest rate for the entire loan term. Variable-rate auto loans will produce different results as the rate changes over time. The calculator does not model variable-rate scenarios.

Sales tax is applied to the full vehicle price in this calculator. In some states, sales tax is calculated on the net price after the trade-in allowance is subtracted. Check your state’s specific rules for the most accurate tax calculation.

The amortization model assumes the first payment is due exactly one month after loan origination (standard end-of-period amortization). Some lenders use a daily simple interest method, which can produce slightly different payment amounts depending on when payments are made during the month.

The calculator does not model prepayment, extra payments, or lump-sum payoffs. Making additional principal payments will reduce your total interest paid and shorten your loan term, but these scenarios require a separate amortization schedule tool.

GAP insurance, extended warranties, credit life insurance, and other dealer add-on products are not included unless you manually add their cost to the Fees field. Results are estimates for planning and comparison purposes only. Always verify figures with your lender before signing a loan agreement, as lender-specific rounding rules, origination fees, and prepaid interest may cause minor differences from these estimates.

Frequently Asked Questions

What credit score do I need to get a good car loan interest rate?

Most lenders use tiered pricing based on credit score ranges. Borrowers with scores above 720 (often called “super prime”) typically qualify for the lowest advertised rates. Scores between 660 and 719 (prime) usually receive rates that are 1–3 percentage points higher. Scores below 620 (subprime) may still qualify for financing but at significantly higher rates — sometimes 10% or more — which dramatically increases the total cost of the loan. Before applying, check your credit report for errors and, if possible, spend a few months improving your score by paying down revolving balances and making all payments on time. Even a 30-point improvement can move you into a lower rate tier and save hundreds of dollars in interest.

Should I make a larger down payment or keep the cash and invest it?

This depends on the interest rate on your auto loan compared to the expected return on your investment. If your loan rate is 7% and you believe you can reliably earn more than 7% after tax by investing the cash, keeping the cash and making a smaller down payment may be mathematically advantageous. However, a larger down payment reduces your monthly payment, lowers the risk of negative equity, and eliminates the uncertainty of investment returns. For most buyers, especially those with rates above 5–6%, putting more down is the lower-risk choice. Use this calculator to quantify exactly how much interest a larger down payment saves, then compare that figure to your realistic investment expectations.

Can I negotiate the interest rate offered by a dealership?

Yes, and you should always try. Dealers often act as intermediaries between buyers and lenders, and they are sometimes permitted to mark up the rate above what the lender actually requires — keeping the difference as profit. The most effective negotiating tool is a pre-approval from your own bank or credit union. When you walk into a dealership with a competing offer in hand, the dealer’s finance department must either match or beat that rate to earn your business. Always ask the dealer to show you the “buy rate” — the rate the lender actually charges — versus the rate being offered to you. Even a 0.5% reduction in APR on a $25,000 loan over 60 months can save over $350 in total interest.

What is the ideal loan term for a car loan?

There is no single ideal term, but most financial experts suggest keeping auto loans to 48 or 60 months when possible. These terms balance a manageable monthly payment with a reasonable total interest cost and reduce the time you spend in negative equity. Loans of 72 months or longer are increasingly common but carry meaningful risks: the vehicle depreciates faster than the loan balance decreases in the early years, meaning you could owe more than the car is worth for several years. If a 48- or 60-month payment is unaffordable, that is often a signal that the vehicle price is too high for your current budget rather than a reason to extend the term.

How does refinancing a car loan work, and when does it make sense?

Refinancing replaces your existing auto loan with a new loan, ideally at a lower interest rate or shorter term. It makes the most sense when interest rates have dropped since you took out your original loan, your credit score has improved significantly, or you originally financed through a dealer at a higher-than-market rate. To refinance, you apply with a new lender — typically a bank, credit union, or online auto lender — who pays off your existing loan and issues a new one. Use this calculator to compare your current loan’s remaining cost against a refinanced scenario by entering your current payoff balance as the vehicle price and setting the down payment and trade-in to zero. Be aware that refinancing resets your loan term, so refinancing into a longer term may lower your payment but increase total interest paid.

What fees are typically rolled into a car loan, and which should I pay upfront?

Common fees that are frequently financed into auto loans include dealer documentation fees (typically $100–$800), title and registration fees, and sometimes GAP insurance or extended warranty premiums. Financing these fees means you pay interest on them for the life of the loan, increasing their true cost. Fees that are better paid upfront — if you have the cash — include registration and title fees, since these are fixed government charges with no negotiating room. Documentation fees are sometimes negotiable, particularly in states that cap them by law. Always ask the dealer for an itemized breakdown of all fees before agreeing to finance them, and enter the total into this calculator’s Fees field to see their impact on your monthly payment and total interest.

What is GAP insurance, and do I need it on a car loan?

GAP (Guaranteed Asset Protection) insurance covers the difference between what you owe on your auto loan and what your vehicle is worth if it is totaled or stolen. Because cars depreciate quickly — sometimes losing 15–25% of their value in the first year — it is common for borrowers to owe more than the car’s market value, especially in the early months of a long-term loan. If your car is totaled, standard auto insurance pays only the current market value, leaving you responsible for the remaining loan balance. GAP insurance covers that gap. It is most valuable when you make a small down payment, choose a long loan term, or finance a vehicle that depreciates rapidly. Dealers offer GAP coverage, but it is often available at lower cost through your auto insurer or credit union.

Is 0% APR financing really free, and how do I know if it is the best deal?

Zero-percent APR financing means you pay no interest on the loan, which sounds ideal — but manufacturers offering these promotions typically require buyers to forgo a cash rebate that could otherwise be applied as a down payment or used to reduce the purchase price. To determine which option is better, calculate the total cost under 0% APR (simply the loan principal times the number of payments, since there is no interest) and compare it to the total cost of taking the cash rebate and financing the reduced balance at a market rate using this calculator. In many cases, especially when market rates are low and the rebate is large, taking the rebate and financing at a competitive rate saves more money than 0% APR. Always run both scenarios before deciding.