McHenry County Sales Tax on Cars: Rates, Trade-Ins, and Fees

If you buy a car from a dealership in McHenry County, the sales tax on cars runs 7.00% in most of the county, combining Illinois’s 6.25% state rate with a 0.75% Regional Transportation Authority tax. Buy privately from another person, though, and you pay a flat Illinois Vehicle Use Tax instead, often a much smaller number. What you actually owe depends on where you live, who you buy from, whether you trade in a vehicle, and how old the car is.

The 7.00% Dealership Rate

Illinois charges a 6.25% Retailers’ Occupation Tax on most retail sales, including vehicles sold by dealers.1Illinois General Assembly. 35 ILCS 120/2-10 – Rate of Tax McHenry County sits inside the Regional Transportation Authority’s six-county region, which layers on another 0.75%.2Illinois Department of Revenue. Mass Transit District Sales Tax Combined, that is 7.00% for most residents.

The 0.75% RTA figure already reflects a 0.25% increase authorized by the NITA Act in late 2025. The RTA expected that increase to take effect in August 2026, so purchases closed before then may still be taxed at the earlier 6.75% combined rate.3Regional Transportation Authority. Moving the System

Several municipalities in the county impose home rule sales taxes that push the rate above 7.00%. The rate is tied to your home address, not where the dealership sits, so verify your exact rate with the Illinois Department of Revenue’s online tax rate finder before you sign.

Private Party Sales Use a Flat Tax

When you buy from another individual, the transaction falls under the Illinois Vehicle Use Tax, which charges a flat dollar amount rather than a percentage.4Illinois General Assembly. 35 ILCS 120/2-10 – Rate of Tax For vehicles sold for less than $15,000, the tax is set by how many years have passed since the model year:5Illinois General Assembly. 86 Illinois Administrative Code 151 – Vehicle Use Tax

  • 1 year or less after model year: $465
  • 2 years: $365
  • 3 years: $290
  • 4 years: $240
  • 5 years: $190
  • 6 years: $165
  • 7 years: $155
  • 8 years: $140
  • 9 years: $125
  • 10 years: $115
  • Over 10 years: $100

If the vehicle sells for $15,000 or more, the flat tax is based on the purchase price:5Illinois General Assembly. 86 Illinois Administrative Code 151 – Vehicle Use Tax

  • $15,000 to $19,999: $850
  • $20,000 to $24,999: $1,100
  • $25,000 to $29,999: $1,350
  • $30,000 to $49,999: $1,600
  • $50,000 to $99,999: $2,600
  • $100,000 to $999,999: $5,100
  • $1,000,000 and over: $10,100

The gap can be significant. A $25,000 car bought from a dealer at 7.00% carries $1,750 in sales tax; the same car bought privately costs $1,350 in Vehicle Use Tax. A 12-year-old car bought privately for $5,000 owes $100, while a dealer sale at the same price would generate $350.

Transfers Between Family Members

Transfers between close family members qualify for a reduced flat tax of $15 per vehicle. The qualifying relationships are limited to a spouse, parent, brother, sister, or child, including an adopted child.5Illinois General Assembly. 86 Illinois Administrative Code 151 – Vehicle Use Tax Stepchildren, in-laws, grandparents, and grandchildren do not qualify.

The same $15 rate applies when a vehicle passes to a beneficiary through estate administration, or when it moves between related business entities without a change in beneficial ownership. You still file Form RUT-50 and provide proof of the family relationship.

How Trade-Ins and Rebates Change the Bill

Trading in a vehicle at a dealership reduces the amount you pay tax on. You owe the percentage-based sales tax only on the difference between the new vehicle’s price and the trade-in credit.6Illinois General Assembly. 35 ILCS 120 – Retailers Occupation Tax Act Buy a $30,000 vehicle, trade in your old one for $10,000, and you owe tax on $20,000. At 7.00%, that saves you $700.

Manufacturer rebates work differently. When a manufacturer reimburses the dealer for a rebate, Illinois treats the full pre-rebate price as the taxable amount.7Illinois Department of Revenue. Illinois Department of Revenue – Taxpayer Answer Center A $2,000 manufacturer rebate on a $35,000 car may cut your out-of-pocket price to $33,000, but the tax is still calculated on $35,000. A discount the dealer itself offers, with no outside reimbursement, does reduce the taxable price.

Private party sales use the flat-tax structure, so trade-in credits between individuals do not offset the Vehicle Use Tax.

Buying From an Out-of-State Dealer

Buying a vehicle from a dealer outside Illinois and bringing it into McHenry County still triggers Illinois tax. You file Form RUT-25 within 30 days of bringing the vehicle into the state.8Illinois Department of Revenue. Vehicle Use Tax Transaction Return Instructions

Illinois credits you for sales tax already paid to the other state. If Missouri collected 4% on a $30,000 vehicle, you owe Illinois the difference between your full Illinois rate and that 4%. Attach proof of payment when you file. The Secretary of State will not process your title or registration without a completed RUT-25 and proof of tax payment or exemption.8Illinois Department of Revenue. Vehicle Use Tax Transaction Return Instructions

One important exception: if you owned the vehicle for more than three months in another state before moving to Illinois, no Illinois tax is due. You still file RUT-25 to document the exemption, but the tax line is zero.9Illinois Department of Revenue. Illinois Tax Requirements for Cars, Trucks, Vans, Motorcycles, ATVs, Trailers, and Mobile Homes

Forms, Deadlines, and Penalties

When you buy from a dealer, the dealer files Form ST-556 with the Illinois Department of Revenue and collects the tax at the time of sale.10Illinois Department of Revenue. ST-556 Sales Tax Transaction Return Instructions Nothing separate is required from you.

Private party purchases put the paperwork on the buyer. You must file Form RUT-50 and pay the Vehicle Use Tax within 30 days of acquiring the vehicle.11Illinois Department of Revenue. RUT-50 Instructions for Private Party Vehicle Use Tax Transaction File through MyTax Illinois, or submit the form in person at a Secretary of State Driver Services facility along with your title and registration application.12Illinois Department of Revenue. RUT-50, Private Party Vehicle Use Tax Transaction Instructions If you file online, print a copy for the Secretary of State; they won’t process your title without it.

Missing the 30-day window triggers penalties. Illinois charges a late filing penalty if a processable return isn’t submitted by the due date, a separate late payment penalty if the tax isn’t paid on time, and a cost-of-collection fee if a bill goes unpaid more than 30 days after it’s issued.11Illinois Department of Revenue. RUT-50 Instructions for Private Party Vehicle Use Tax Transaction The cleanest fix is to handle the paperwork the same week you buy the car.

Fees That Stack on Top of the Tax

Tax is only part of what you’ll pay. The Illinois Secretary of State adds several fees that catch some buyers off guard.

On a $5,000 private-party purchase, the $100 Vehicle Use Tax plus $165 title plus $151 plates puts your government costs at $416 before the first drive. Dealers usually fold these fees into your closing paperwork, but you’re still paying them.

Electric Vehicles

Electric vehicles pay the same sales tax or Vehicle Use Tax as any other car in McHenry County. There is no state-level sales tax exemption for EVs, and the $100 annual registration surcharge applies on top of the $151 plate fee.14Illinois Secretary of State. Electric Vehicle License Plates – ILSOS.gov

Beginning July 1, 2026, Illinois residents who buy an all-electric passenger vehicle in-state can apply for a $2,000 rebate through the Illinois Clean Energy Jobs Act program. Applications must be submitted within 90 days of purchase, and the rebate does not reduce your taxable amount; the full sales tax is still owed at closing, and the rebate arrives as a separate payment after the fact.