Louisiana Auto Loan Calculator (with Louisiana Sales Tax & Fees)

Louisiana taxes vehicle purchases at a 4.45% state sales tax rate, which this calculator applies directly to the vehicle's purchase price before financing. That tax, along with a flat title, registration, and documentation fee estimate, gets added to the sticker price and then reduced by your down payment and trade-in value to arrive at the amount you actually finance. From there, the calculator runs a standard fixed-rate amortization schedule to compute your monthly payment and total finance charge over the loan term.

This tool is built for Louisiana residents budgeting for a car purchase who want to see the real, tax-inclusive monthly payment rather than a number based on the sticker price alone. Because Louisiana's state rate is relatively low compared to many neighboring states, the tax line item here tends to be a smaller share of the total deal than in higher-tax states, but it is still a meaningful add-on that shopping tools quoting sticker-price-only payments will miss entirely.

The calculator works through the purchase in a fixed sequence:

1. Sales tax on the vehicle price. Louisiana's 4.45% state rate is multiplied directly against the vehicle purchase price: $\text{Tax} = \text{Price} \times 0.0445$.
2. Title, registration, and documentation fees. A flat $350 estimate is added to cover the paperwork costs associated with titling and registering a vehicle in Louisiana.
3. Total vehicle cost. Purchase price plus sales tax plus fees gives the full out-the-door cost before any down payment is applied.
4. Financed amount. Your down payment and trade-in value (combined into one input) is subtracted from the total vehicle cost. If the down payment exceeds the total cost, the financed amount floors at $0.
5. Amortized monthly payment. The financed balance is run through the standard fixed-payment amortization formula, $A = P \times \frac{i(1+i)^n}{(1+i)^n-1}$, where $i$ is your APR divided by 12 and $n$ is the loan term in months, producing a level monthly payment for the life of the loan.
6. Total finance charge. Summing every period's interest across the full amortization schedule gives the total interest cost over the loan term.

All of this uses decimal-precision arithmetic rather than floating-point math, so the schedule reconciles exactly to the penny across all 60 (or however many) payments rather than drifting from small rounding errors.

Using the default scenario: a $35,000 vehicle, $5,000 down payment and trade-in, a 60-month loan term, and a 7.25% APR.

1. Sales tax: $35,000 \times 4.45\% = \$1,557.50$.
2. Fees: a flat $350.
3. Total vehicle cost: $35,000 + \$1,557.50 + \$350 = \$36,907.50$.
4. Financed amount: $36,907.50 - \$5,000 = \$31,907.50$.
5. Monthly payment: amortizing $31,907.50 at 7.25% APR over 60 months yields a payment of approximately $635.58.
6. Total finance charge: over the full 60-month term, total interest comes to roughly $6,227.

Compare that to a buyer who budgets only against the $35,000 sticker price and ignores tax and fees: they would underestimate the amount financed by nearly $2,000, and their real monthly payment would come in noticeably higher than expected once the paperwork is finalized at the dealership.

• Parish and local sales taxes. Louisiana permits parishes and municipalities to levy additional local sales taxes on top of the 4.45% state rate, and vehicle purchases are frequently subject to these local add-ons depending on where the buyer resides. This calculator applies only the flat state rate, so your actual tax bill may be higher depending on your parish.
• Trade-in tax credit nuances. Louisiana law generally allows a trade-in allowance to reduce the taxable amount when trading with a licensed dealer, which can lower the effective tax paid versus a straight percentage of the full purchase price. This calculator combines down payment and trade-in into a single post-tax input and does not model a trade-in tax credit.
• Dealer add-ons. Extended warranties, GAP insurance, paint protection, and similar add-on products are not included in the base price or the financed amount.
• Credit-score-based rate variation. The APR you actually qualify for depends on your credit profile and the lender; this calculator uses whatever rate you enter as a flat input.
• Sales tax caps or exemptions. Certain transactions (gifts between family members, some out-of-state transfers) may be exempt from the standard tax treatment modeled here.

• Budgeting off the sticker price alone. Buyers who plan a monthly payment around the vehicle price without adding tax and fees are routinely surprised when the actual financed amount, and therefore the payment, comes in higher at signing.
• Forgetting that a lower down payment increases the financed balance and the total interest paid, not just the monthly payment; the interest cost compounds over the life of a larger loan.
• Assuming the advertised APR is the rate you'll receive. Advertised rates are typically reserved for the most creditworthy borrowers; actual approved rates vary.
• Not shopping the loan term. A 72-month term lowers the monthly payment shown here but meaningfully increases total interest paid compared to a 48- or 60-month term at the same rate.
• Overlooking parish-level local tax add-ons when comparing this estimate to a dealer's final "out the door" quote.

• Louisiana Department of Revenue: State sales and use tax rate schedules applicable to vehicle purchases.
• Louisiana Office of Motor Vehicles: Title and registration fee schedules for passenger vehicles.
• Consumer Financial Protection Bureau: Guidance on auto loan financing, APR disclosure, and amortization mechanics under Regulation Z.