Bill of Sale for an Automobile in Colorado: What It Is and How It Works

When you buy or sell a car in Colorado, a bill of sale serves as the written record of that transaction. It documents who sold the vehicle, who bought it, what was exchanged, and under what terms. Colorado doesn't always require a bill of sale the way some states do — but having one protects both parties and can smooth out the title transfer process at the DMV.

What a Colorado Automobile Bill of Sale Actually Does

A bill of sale is a simple legal document that records the transfer of ownership from seller to buyer. It's not the same as a title. The title is the official government document proving ownership — a bill of sale is the private record of the deal that led to the title changing hands.

In Colorado, the bill of sale becomes especially useful when:

• The purchase price affects how sales tax is calculated at registration
• There's a dispute later about what was agreed to
• The vehicle is sold "as-is" and you want that documented in writing
• A lien release or other paperwork is delayed and you need proof the sale occurred

Colorado's Division of Motor Vehicles uses the reported sale price to determine the taxable value of the vehicle. If a bill of sale isn't present, the DMV may assess taxes based on book value instead — which can sometimes be higher than what was actually paid.

What to Include in a Colorado Vehicle Bill of Sale 📋

Colorado doesn't mandate a single official bill of sale form for private vehicle sales, though the state does offer a Bill of Sale (DR 2116) form through the DMV. You can use that form, or create your own document — as long as it captures the essential details.

A complete bill of sale for a Colorado automobile should include:

If the vehicle is a gift or sold between family members, the bill of sale should still be completed — noting the relationship and the $0 or token sale price. Colorado has specific rules around gift vehicle transfers that affect how taxes are applied, and documentation helps support those claims.

Private Sale vs. Dealer Sale: Different Rules Apply

Private party sales are where a bill of sale matters most. When you buy from a dealership, the dealer handles most of the paperwork and typically generates their own purchase agreement, which functions similarly. In a private sale, neither party has that infrastructure — the bill of sale is often the only written record that exists.

For private sales, both the buyer and seller should keep a signed copy. The seller's copy can protect them if the buyer later fails to transfer the title and traffic violations or tolls accumulate under the old owner's name. The buyer's copy proves what was paid if the tax assessment at registration is questioned.

Odometer Disclosure Requirements 🚗

Federal law requires an odometer disclosure for most motor vehicles under 10 years old. In Colorado, this is typically handled on the title itself — there's a section on the back of the title where the seller fills in the mileage and both parties sign. If you're using a separate bill of sale, it's good practice to include the odometer reading there as well, even if it's also captured on the title.

Vehicles over 10 model years old are generally exempt from federal odometer disclosure requirements, but including the mileage anyway is a reasonable habit.

Title Transfer and the Bill of Sale Together

In Colorado, transferring a title after a private sale involves more than just the bill of sale. The process generally includes:

• Signing the back of the title — seller signs it over to the buyer, including odometer disclosure
• Completing the bill of sale — documents the sale price and conditions
• Visiting a county motor vehicle office — title transfers happen at the county level in Colorado, not at a single central DMV location
• Paying applicable fees and taxes — which are based in part on the sale price documented in the bill of sale

The buyer typically has a set number of days after purchase to complete the title transfer. That window varies and is set by state law — late transfers can result in penalty fees.

Where Things Get Complicated

Several factors shape exactly how a Colorado vehicle bill of sale functions in practice:

• Vehicle type — motorcycles, trailers, off-highway vehicles, and commercial trucks may have different documentation requirements
• Salvage or rebuilt titles — these involve additional steps beyond a standard sale
• Out-of-state vehicles — bringing a car into Colorado from another state adds inspection and documentation layers
• Liens on the title — if the seller still owes money on the vehicle, the lienholder must be satisfied before a clean title can transfer

The bill of sale is one piece of a larger process. How straightforward or complicated that process becomes depends on the vehicle's history, the county you're registering in, and the specific circumstances of the sale.