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Buying a Car: How Do You Know a Car’s In-Service Date?

A car’s in-service date relates to the original sale of the vehicle. So if you’re interested in buying a car with a certified pre-owned (CPO) warranty or with some amount of remaining factory warranty, you need to know about this term.

This term applies to the day a car got sold to the first owner. But why is it so important? And how exactly do you calculate it?

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Why Is It So Important?

An in-service date is important because it’s not only the date the car is originally sold but also the date a car’s warranty begins. And it’s not just the warranty. The original sales date can be used to calculate when other perks began, such as free scheduled maintenance (if a car includes it), free factory trials of features such as SiriusXM radio and dealer-installed extras.

So if you’re interested in buying a used car with some warranty life left, it’s obvious why the in-service date is so important: It’s how you calculate when your warranty expires, and the manufacturer no longer covers your repairs. A simple model year isn’t good enough because it doesn’t tell you everything you need to know.

A 2021 car, for example, may have been sold at any point from early 2020 through the end of 2021 — or even later.

An in-service date is also used for calculating most certified pre-owned warranties. While some CPO warranties begin the day a buyer purchases the used car, most start on the day the dealer originally sold the car. In other words, knowing the car’s in-service date can be a huge benefit because it determines exactly how much warranty you’ll get with your certified pre-owned car.

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How Do You Calculate It?

Now that you know why the in-service date is so important, you’ll probably be curious how you calculate it. Unfortunately, there’s no simple answer.

The best way to find out a car’s in-service date is to call up your local dealership and find out for sure. If you’re interested in a Kia, for instance, you’ll want to call up a Kia dealership’s service department and ask when the car originally went into service.

Most dealerships will have no problem giving you this information over the phone at no charge. If you’re buying a car from a dealer, you should expect this information to be included before the sale is finalized, so you know exactly how much warranty you have left.

If you’re negotiating a car deal on a day when a dealership’s service department is closed, you may want to check the car’s vehicle history report from AutoCheck or Carfax.

Both of these reports will give you the car’s original sale date, and while it may not precisely match the dealer’s official figure, it will give you a great idea about when your warranty likely began — and when it’s set to expire.

Related Stories about Car Buying:

Autotrader’s Renee Valdes contributed to this report

Doug Demuro
Doug DeMuro writes articles and makes videos, mainly about cars. Doug was born in Denver, Colorado, and received an economics degree from Emory University in Atlanta. After graduation, Doug spent three years working for Porsche Cars North America. Eventually, he quit his job to become a writer, largely because it meant that he no longer had to wear pants. Doug’s work has been featured in a... Read More about Doug Demuro


How to Find a Car's In-Service Date?

The easiest way to find your car’s in-service date is by calling the dealership where you purchased, or are planning to purchase, the vehicle from.

Is There a Warranty on Used Cars?

This depends on when the car was originally sold. Some used vehicles will have warranties left on them, but you should talk to the dealer about the amount of warranty left before purchasing the car.

Should You Buy a Warranty on a Used Car?

Having a warranty can come in handy, but it may not be for everyone. Check to see if the car has an existing warranty on it before opting to purchase one.

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  1. What if your in-service date was 6 months prior to you buying it and the dealership sold it to me as new. Could it have been owned before even if the titling history equals “1”, which means me?

    • You are first owner. Dealerships can activate warranty and not title the vehicle. It’s sold new to you because the car was never titled. Warranty has nothing to due with title.

      When the dealer used the car before you bought it, it wasn’t registered and they would have been using dealer transport temp tags.

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