A bill of sale for a car in Illinois is not legally required, but writing one is one of the smartest moves a private buyer or seller can make. Ownership itself transfers through the certificate of title, which the seller signs over and the buyer submits to the Secretary of State within 20 days of delivery.1Illinois General Assembly. Illinois Compiled Statutes 625 ILCS 5/3-112 The bill of sale does something the title cannot: it captures the price, the condition, the payment method, and any side terms the two of you actually agreed to. If a dispute comes up later, or the state questions what you paid, that piece of paper is your evidence.
What to Put in an Illinois Bill of Sale
Illinois doesn’t publish a standard form and doesn’t dictate the contents, which means you have to be thorough on your own. A thin bill of sale isn’t much better than none.
Include, at a minimum:
- Full legal names and current addresses for both buyer and seller.
- A complete vehicle description: year, make, model, body type, color, and Vehicle Identification Number. The VIN is the anchor because it’s unique to the vehicle and matches the title.
- The odometer reading at the time of sale. It should match the mileage the seller records on the title assignment.
- The sale price and the form of payment (cash, check, or otherwise). This figure drives the use tax calculation.
- The date of sale. This is when the buyer’s 20-day title transfer clock starts.
- A statement of condition and warranty. Most private sales are as-is, meaning the buyer takes the vehicle in its current condition with no guarantees from the seller. Say so explicitly.
- Signatures from both parties, dated. Illinois doesn’t require signatures on a bill of sale, but an unsigned document is far weaker as evidence. Notarization is optional and adds a layer of verification if authenticity is ever challenged.
Print two originals so both parties keep one. Store yours with your vehicle records and don’t throw it away when you sell the car years later; it can still matter for tax records and title questions.
Why the Price on Your Bill of Sale Matters for Illinois Use Tax
This is where the document earns its keep. Illinois charges a Private Party Vehicle Use Tax on private sales, paid by the buyer using Form RUT-50 at the time of title transfer.2Illinois Department of Revenue. RUT-50 Instructions for Private Party Vehicle Use Tax Transaction
The tax owed depends on the vehicle’s purchase price or, when there is no stated price, its fair market value.3Illinois Department of Revenue. Use Tax Rates For vehicles under $15,000, the tax is a flat amount tied to the vehicle’s age; for vehicles at $15,000 or more, it’s a flat amount tied to price brackets.4Illinois Department of Revenue. Private Party Vehicle Use Tax Chart for 2026
Here’s the practical piece. If the buyer arrives at the Secretary of State’s office with no documentation of what they paid, the state has no reason to accept a low figure and can assess tax on fair market value instead. For a car that sold cheaply because it needed a transmission or had hail damage, that gap can amount to hundreds of dollars. A signed bill of sale showing the actual price is what the buyer presents to defend the number on the RUT-50.
Two exceptions are worth knowing. Transfers between spouses, parents, siblings, or children qualify for a reduced tax of $15. Motorcycles and ATVs are taxed at a flat $25 regardless of value.2Illinois Department of Revenue. RUT-50 Instructions for Private Party Vehicle Use Tax Transaction
Odometer Disclosure and the 2011 Rule
For any vehicle from model year 2011 or newer, the seller has to record the current mileage on the title assignment and indicate whether the reading is accurate, whether it has exceeded the odometer’s mechanical limits, or whether the mileage shown is not the actual mileage.5Illinois General Assembly. Illinois Compiled Statutes 625 ILCS 5/3-104
Vehicles from model year 2010 or earlier are exempt from federal odometer disclosure. The exemption is tied to the calendar year, not a rolling age, so a 2011 model year vehicle stays subject to disclosure until calendar year 2031.6eCFR. 49 CFR Part 580 – Odometer Disclosure Requirements
Record the mileage on your bill of sale either way. If the buyer later says you rolled back the odometer or misstated the mileage, you want a written figure with your signature next to it. The number in the bill of sale should match what goes on the title assignment.
The Seller’s Report of Sale Protects You After the Handoff
Sellers skip this one all the time, and it’s the omission most likely to cause real trouble. When you sell an Illinois-titled vehicle, you’re supposed to complete a Seller’s Report of Sale (Form VSD 703) and mail it to the Secretary of State right away.7Illinois Secretary of State. Seller’s Report of Sale
Until the buyer transfers the title, the vehicle stays associated with your name in state records. If the buyer drags their feet and racks up red-light tickets, parking violations, or gets into a crash, those problems can find their way back to you. The VSD 703 creates an official date-stamped record that you no longer own the car. Your bill of sale supports that with the detail of who bought it and for how much, but the VSD 703 is the form the state actually tracks.
Selling a Car That Still Has a Lien on It
If you still owe money on the vehicle, the lienholder is printed on the certificate of title, and the Secretary of State will not issue a clean title to the buyer until the lien is satisfied. You need an original lien satisfaction letter from your lender on their official letterhead. With that letter in hand, you can complete the title transfer through the Electronic Registration and Title system and remove the lienholder from the lien section of the application.8Illinois Secretary of State. Title and Registration Checklist – Lien Paid
Ask your lender for the payoff letter before you list the car. You cannot deliver a clean title without it.
Your bill of sale should state whether the vehicle is sold free of liens. If the buyer’s money is going directly to the lender to pay off the loan, spell that arrangement out in writing. Informal handshake versions of this deal are exactly where private sales go wrong.
What Happens Without a Bill of Sale
Three scenarios come up repeatedly.
The first is the use tax dispute. A buyer with no proof of price may be assessed tax on fair market value rather than the discounted price actually paid. For a mechanically rough or cosmetically damaged car, that difference is real money.
The second is a disagreement between buyer and seller. Without a written record there’s no way to prove what was said about the vehicle’s condition, whether the sale was as-is, or what the agreed price was. If the buyer later claims you promised a recent transmission rebuild or a clean accident history, you’re in a word-against-word argument. An as-is disclaimer with specific condition notes closes that door.
The third involves a lost or damaged title before the buyer can submit it. A bill of sale won’t replace the title, but it supports a duplicate title application by confirming that the transaction happened and identifying who the vehicle went to.
None of this makes a bill of sale legally mandatory in Illinois. It just makes it the cheapest insurance policy either side of a private car sale can buy.