Yes. A Colorado bill of sale for a car is required any time a vehicle changes hands between private parties. The buyer needs it to title and register the vehicle at the county motor vehicle office, and the county clerk uses the price written on it to calculate sales tax owed on the purchase.1Department of Revenue – Motor Vehicle. Buyer’s and Seller’s Responsibilities
What the Bill of Sale Must Contain
The Colorado DMV sets a short list of required details: the vehicle’s year, make, and VIN, the time and date of the sale, and signatures from both buyer and seller.1Department of Revenue – Motor Vehicle. Buyer’s and Seller’s Responsibilities That is the floor. A workable bill of sale goes a little further and includes:
- Full legal names and current addresses for the buyer and the seller.
- Year, make, model, and complete Vehicle Identification Number.
- The agreed purchase price in dollars. The clerk relies on this figure for sales tax, so write it accurately.
- The date and the time of the sale. The time matters if the buyer plans to drive the car home before registering it.
- Signatures from both parties.
Colorado does not require the bill of sale to be notarized. A signed document carrying the information above is valid.
Do You Have to Use the DR 2173 Form?
No. Colorado publishes an official form called the Secure Motor Vehicle Bill of Sale (DR 2173), but it is classified as a Title Secure Form and is not available as a free download. It has to be purchased through authorized vendors such as the Colorado Auto Dealers Association, the Colorado Independent Automobile Dealers Association, or A-B-C Enterprises.2Department of Revenue – Motor Vehicle. Department of Revenue – Motor Vehicle Forms
You can write your own bill of sale or use a generic template instead, as long as it carries the required information and both parties sign it. The DR 2173 earns its keep in one specific situation: when the odometer disclosure needs to be made somewhere other than the Certificate of Title, because the form has a dedicated section for it.1Department of Revenue – Motor Vehicle. Buyer’s and Seller’s Responsibilities For a straightforward sale where the odometer reading goes on the title itself, a handwritten bill of sale works.
Odometer Disclosure
Federal law requires an odometer reading when a vehicle changes hands, and Colorado enforces it. The seller completes the disclosure either on the Certificate of Title or on the DR 2173 bill of sale, including the current mileage and whether the reading is actual, not actual, or exceeds the odometer’s mechanical limits.1Department of Revenue – Motor Vehicle. Buyer’s and Seller’s Responsibilities
Vehicles that are 20 or more model years old are exempt from the federal odometer disclosure. In 2026, that covers any 2006 or older model year. Anything 2007 or newer still needs the disclosure.
Driving the Car Home Before Registering It
The bill of sale does more than record the price. Under C.R.S. § 42-3-115, a buyer in a private-party sale can legally drive the vehicle home without registration for up to 36 hours, but only when the sale happened on a weekend, holiday, or between 5 p.m. and 8 a.m., the buyer is driving directly from the seller’s storage location to the buyer’s own, and the signed bill of sale showing the time and date of sale is inside the vehicle along with proof of insurance.3Justia Law. Colorado Code Title 42 – Section 42-3-115
Every one of those conditions has to be true. A sale at 3 p.m. on a Tuesday does not qualify. Neither does a detour on the way home. If your situation falls outside that window, the alternative is a temporary registration permit from your county motor vehicle office; you’ll need the bill of sale, proof of insurance, and a valid ID to get one.1Department of Revenue – Motor Vehicle. Buyer’s and Seller’s Responsibilities
What the Seller Still Has to Do
Handing over a signed title and bill of sale is not the end of the seller’s exposure. Two more steps matter.
Take the plates off. Colorado plates belong to the registered owner, not the vehicle. If you leave them on, toll charges, traffic violations, and other incidents involving the car can still land on you.1Department of Revenue – Motor Vehicle. Buyer’s and Seller’s Responsibilities
File a report of sale within five days. You can do this online through myDMV.colorado.gov or in person at the county motor vehicle office. The step is technically optional. Skipping it is a gamble: if the buyer drags out registration or never files, the vehicle stays in your name in state records, and anything that happens with it points back to you.1Department of Revenue – Motor Vehicle. Buyer’s and Seller’s Responsibilities
At the moment of sale, properly endorse the Certificate of Title. Sign it, enter the purchase price and date, and fill in the buyer’s name and address. Under C.R.S. § 42-6-110, the seller affirms the sale under penalty of perjury. If the title lists multiple owners, every owner must print and sign.4Justia Law. Colorado Code Title 42 – Section 42-6-110
What the Buyer Does Next
The buyer has 60 days from the sale to apply for a new Certificate of Title and register the vehicle at the county motor vehicle office. Miss that window and late fees apply.4Justia Law. Colorado Code Title 42 – Section 42-6-110 Bring:
- The signed Certificate of Title, with the purchase price, date, and buyer information filled in by the seller.
- The bill of sale showing what you paid.
- The completed odometer disclosure, either on the title or on a DR 2173.
- Proof of insurance.
- Secure and verifiable identification, such as a Colorado driver’s license or ID card.
The clerk collects sales tax based on the purchase price on the bill of sale, plus title and registration fees.5Department of Revenue – Motor Vehicle. Titling a Vehicle If a lender is recording a lien on the vehicle, you’ll also need a mortgage document showing the vehicle description, lienholder information, lien amount, and your signature.
Gifted Vehicles
A vehicle given as a gift is not subject to sales or use tax on the transfer, but the person giving the gift must have already paid tax on their own acquisition, and the clerk will want proof of that before titling the vehicle in the new owner’s name.6Colorado Department of Revenue. Sales and Use Tax Topics – Motor Vehicles A bill of sale is still worth doing. Record the transaction as a gift with a purchase price of $0, keep the vehicle details and both signatures, and you have a clear record of when ownership changed.
Front Range Emissions Testing
If the vehicle is being bought or sold in the Denver metro area or along the Front Range, a passing emissions test is a separate requirement for registration. The program covers Adams, Arapahoe, Boulder, Broomfield, Denver, Douglas, El Paso, Jefferson, Larimer, and Weld counties, and the seller is responsible for providing the buyer with a passing test that has not already been used for a prior registration or renewal.7Department of Revenue – Motor Vehicle. Emissions New gasoline vehicles are exempt for seven model years and new diesels for four, but a vehicle sold in the final year of its exemption still needs a test for the transfer.