A car purchase agreement is the legal contract between you and the seller that documents the sale
A purchase agreement (also called a bill of sale or sales contract) is the document that records what you are buying, what you are paying, and the condition of the vehicle. It protects both you and the seller by creating a written record of the transaction. Without one, you have no proof of the price you agreed to, no documentation of what was included, and no protection if the seller later claims you owe more money or if the vehicle has undisclosed problems.
The agreement does not transfer the title — that happens separately at the DMV or your state's equivalent — but it is the foundation for that transfer. Most private sales use a straightforward one-page form. Dealership sales come with their own multi-page contracts that bundle the purchase agreement with financing terms, warranties, and add-ons.
Key Takeaways
- A purchase agreement must include the vehicle identification number (VIN), the sale price, the condition of the vehicle, and the names and signatures of both buyer and seller.
- Private sales typically use a one-page bill of sale form available free from your state's DMV website or from legal document services.
- Dealership contracts are longer and include financing terms, warranties, and dealer add-ons — read the entire document before signing, not just the price line.
- The agreement should state whether the vehicle is sold "as-is" or with any warranty, and should list any known defects or damage.
- Keep a signed copy for your records; you will need it when you register the vehicle and may need it later if a dispute arises.
What information must be in a purchase agreement
Every purchase agreement needs the same core details, whether it is handwritten on a napkin or a dealership's 15-page contract. The VIN (vehicle identification number) is the most critical — it is the unique 17-character code that identifies that specific car and appears on the title. Without it, the DMV cannot process your registration. The sale price must be stated clearly, including whether that price is final or subject to inspection results or financing approval.
Both the buyer's and seller's full legal names, addresses, and signatures are required. Some states also require driver's license numbers. The agreement should state the vehicle's condition — whether it is sold "as-is" (meaning you accept it in its current state) or with a warranty. If there are known defects, dents, mechanical issues, or damage, list them explicitly. This protects you by documenting what you saw before you bought it, and it protects the seller by showing they disclosed problems rather than hiding them.
The date of sale, the odometer reading, and the vehicle's color and body type should all be included so there is no confusion about which car the agreement covers. Some agreements also note the trade-in value if you are trading in an old vehicle, or the down payment amount if you are financing.
Private sales: using a bill of sale form
If you are buying from an individual rather than a dealership, you will use a bill of sale — a simpler version of a purchase agreement. Most states provide a free template on the DMV website. Search "[your state] DMV bill of sale" to find the official form. If your state does not have one, legal document services like LegalZoom or Nolo offer templates for a small fee, or you can read a generic form from your state's Secretary of State office.
Print two copies — one for you and one for the seller — and fill them out together. Both of you sign and date both copies. Write clearly and do not leave blanks; if a field does not explore, write "N/A" so it is clear you did not just forget to fill it in. Take a photo of the signed agreement on your phone before you leave, in case the paper copy gets lost.
Some states require the bill of sale to be notarized (signed in front of a notary public), though most do not. Check your state's DMV website to see if notarization is required where you live. If it is, you and the seller will both need to sign the form in front of a notary, who will stamp and sign it. Notaries are available at banks, UPS stores, and some libraries, usually for $5 to $15.
Dealership contracts: what to watch for
Dealership purchase agreements are longer and more complex because they bundle several things into one document: the purchase agreement itself, the financing terms (if you are taking a loan), warranty information, and dealer add-ons like extended warranties, paint protection, or gap insurance. Read the entire contract before signing, not just the price section. Dealers often bury terms in the middle pages that you would not expect.
Check the "as-is" or warranty section carefully. Some dealerships sell used cars "as-is," meaning you have no recourse if something breaks the day after you drive off the lot. Others offer a limited warranty — for example, 30 days or 1,000 miles on the powertrain. Know which one applies to your purchase. Look for any add-ons you did not ask for; dealers sometimes pre-check boxes for extended warranties or paint protection and expect you to pay for them. Cross out anything you do not want and initial the change.
The financing section will show the loan amount, interest rate, term (usually 36, 48, 60, or 72 months), and monthly payment. If you are paying cash, this section should say so. Some dealerships include a "spot delivery" clause that lets you drive the car home before financing is finalized; if the financing falls through, you may have to return the car. Ask the dealer to explain any clause you do not understand before you sign.
Condition and "as-is" language
The purchase agreement should clearly state the vehicle's condition and whether you are accepting it "as-is" or with some warranty. "As-is" means the seller makes no promises about the car's mechanical condition, and you cannot come back later claiming the transmission should not have failed. In most states, private sellers can legally sell a car as-is, and you have limited recourse if problems appear after the sale.
If the seller has disclosed known issues — a dent in the door, a check-engine light, worn tires — those should be listed in the agreement so there is no dispute later. If you discovered a problem during a pre-purchase inspection, ask the seller to either fix it, lower the price, or acknowledge it in writing in the agreement. Dealerships in many states are required to disclose known defects, though the rules vary by state and by whether the car is new or used.
If the agreement includes any warranty — even a limited one — make sure you understand what it covers and for how long. A "30-day powertrain warranty" covers the engine, transmission, and drivetrain for 30 days, but not the air conditioning, electrical system, or suspension. Get a copy of the warranty terms in writing, not just a verbal promise.
Signing and keeping your copy
Before you sign, read every page and every line. Do not sign anything you do not understand, and do not let anyone rush you. If the dealer or seller says "just sign here, we can explain it later," that is a red flag. Take your time, ask questions, and do not sign until you are satisfied.
Both you and the seller (or the dealer representative) must sign and date the agreement. Some agreements require initials on each page as well. Make sure you get a fully signed copy — not a photocopy of a blank form, but the actual document with all signatures filled in. Take it home and store it with your other car documents. You will need it when you register the vehicle at the DMV, and you may need it later if a dispute arises about the sale price, the vehicle's condition, or who owns the car.
If you financed the purchase through the dealership, the dealer will keep the original agreement and send you a copy. If you bought from a private seller, you and the seller each keep a signed copy. Do not throw it away after you register the car — keep it for as long as you own the vehicle.
Common mistakes to avoid
The most common mistake is not filling in the VIN correctly. A single wrong digit makes it impossible for the DMV to match the agreement to the title, and you may have to start over. Copy the VIN directly from the vehicle's dashboard or the title document, not from memory or from what the seller tells you.
Another mistake is leaving the price blank or writing it in pencil. Always write the price in ink and spell out the dollar amount in words as well as numbers — "$5,000" and "Five thousand dollars" — so there is no ambiguity. If the price changes after you sign, do not just cross it out and write a new number; both parties should initial the change.
Do not sign a blank agreement or one with blank lines you plan to fill in later. Fill everything in before you sign. Do not agree to a price verbally and plan to write it in later; write it in now. Do not skip the odometer reading; it is required by federal law and helps prevent odometer fraud.
Frequently Asked Questions
Do I need a purchase agreement if I am buying from a private seller?
Yes. A bill of sale is the only proof you have of the price you paid, the vehicle's condition at the time of sale, and that the seller agreed to transfer ownership. Without it, you have no protection if the seller later claims you owe more money or if the title transfer is disputed.
What if the seller will not sign the agreement?
Do not buy the car. A seller who refuses to sign a straightforward bill of sale is signaling that they do not want a written record of the transaction, which usually means they are hiding something — an outstanding loan on the vehicle, a salvage title, or undisclosed damage. Walk away.
Can I use a purchase agreement from the internet, or do I need a lawyer?
For a private sale, a free template from your state's DMV website is sufficient and legally valid. For a dealership purchase, the dealer will provide the agreement. You do not need a lawyer for most car sales, but if the purchase is complicated — for example, you are buying a salvage vehicle or the seller is not the registered owner — consulting a lawyer for $100 to $200 is worth the protection.
What happens if I sign the agreement and then change my mind?
Once you sign a purchase agreement, you are legally bound to the sale. Most private sales do not have a cooling-off period, so you cannot straightforward return the car the next day. Dealerships in some states have a short window (usually 3 days) to cancel, but this varies by state and by the dealer's policy. Check your agreement or ask the dealer before you sign.
Do I need the purchase agreement to register the vehicle at the DMV?
Yes. The DMV will ask for proof of ownership, which is the title, and proof of the sale, which is the bill of sale or purchase agreement. Bring both documents when you register the car. You will also need proof of insurance and a completed registration process.