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

What does a car actually cost to finance in Provo or Ogden once tax is added in? Utah applies its general sales and use tax framework to vehicle purchases, and because most counties and cities layer their own local option rate on top of the state base, this calculator models a blended 6.85% effective rate meant to approximate what a buyer along the Wasatch Front would actually see.

That tax applies to the full negotiated purchase price before any manufacturer rebate is subtracted, though trade-in credit does typically reduce the taxable base, which makes the tax line one of the largest single costs in a Utah vehicle transaction, sometimes exceeding a full year of insurance premiums on the same car. Buyers who focus only on sticker price and advertised APR are often surprised at how much higher the financed amount on the actual contract runs.

This calculator pairs that 6.85% effective rate with a standard amortizing loan and a flat estimate for title transfer, registration, and dealer documentation fees, producing a monthly payment that reflects the real cost of borrowing, not just the price tag.

The engine runs a four-step sequence entirely in Decimal.js arbitrary-precision arithmetic to avoid the rounding drift that plagues ordinary floating-point spreadsheets over a 60-period schedule.

1. Sales tax on the purchase price. Vehicle Price times 6.85% yields the Utah tax owed at the time of sale. For a $35,000 vehicle, that is $35,000 x 0.0685 = $2,397.50.
2. Total transaction cost. The calculator adds a flat $350 estimate covering title transfer, plate and registration fees, and a typical dealer documentation charge, producing Vehicle Price + Sales Tax + Fees.
3. Financed amount. Down payment and trade-in value are subtracted from the total transaction cost to determine the amount actually borrowed: $35,000 + $2,397.50 + $350 - $5,000 = $32,747.50.
4. Amortization. The financed balance is amortized over the chosen term using the standard fixed-rate loan formula, PMT = P x [r(1+r)^n] / [(1+r)^n - 1], where r is the monthly interest rate (annual APR divided by 12) and n is the number of monthly periods.

Using the platform's verified baseline inputs, a $35,000 vehicle price, $5,000 down payment, 60-month term, and 7.25% APR:

• Vehicle price: $35,000.00
• Utah vehicle sales tax (6.85%): $2,397.50
• Title, registration, and documentation fees: $350.00
• Total transaction cost: $37,747.50
• Down payment and trade-in credit: $5,000.00
• Financed amount: $32,747.50
• Monthly rate: 7.25% / 12 = 0.60417%
• Approximate monthly payment over 60 months: about $652
• Approximate total finance charge over the term: roughly $6,391

Extending the term to 72 months lowers the monthly payment but increases total interest paid, since more periods accrue interest against a slower-declining balance. Shortening it to 48 months does the reverse.

• County-specific local option rate variance. Utah's combined vehicle tax rate is not uniform statewide; some counties run slightly below 6.85%, others slightly above, depending on transit district and municipal option taxes layered on the state base.
• Manufacturer rebates versus dealer discounts. How a specific rebate interacts with the taxable base can vary by dealership paperwork and is not modeled here.
• Trade-in payoff shortfalls. If a trade-in has negative equity, that shortfall is typically rolled into the new loan and increases the financed amount beyond what this calculator shows.
• Add-on products. Extended warranties, gap insurance, and gap coverage sold at signing are excluded from the base financed amount.
• Credit-tier pricing. The APR you receive depends on your credit profile and the lender; this tool does not project a rate for you.

• Assuming the sticker price is the taxable base. Trade-in credit generally reduces the taxable amount in Utah, so buyers who ignore that can overestimate their tax liability if not carefully reading their purchase contract.
• Forgetting the $350 fee estimate is approximate. Actual title, registration, and documentation fees vary by vehicle weight class, county, and dealer, so treat this as a planning estimate rather than a final number.
• Comparing loan offers by monthly payment alone. A longer term with a lower payment can still cost more in total interest; always compare total finance charge across term lengths.
• Ignoring how a larger down payment compounds savings. Because interest accrues on the outstanding balance, even a modest increase in cash down reduces both the monthly payment and the lifetime interest cost.
• Overlooking sales tax when budgeting a down payment. Buyers who plan a down payment based only on the vehicle price sometimes find they are short of cash once tax and fees are added to the transaction total.

• Utah State Tax Commission, Motor Vehicle Sales and Use Tax guidance.
• Consumer Financial Protection Bureau (CFPB), Auto Loans resource center.
• Federal Trade Commission (FTC), Understanding Vehicle Financing.
• Utah Division of Motor Vehicles, title and registration fee schedules.