How to Buy the Right Size Head Unit

This article explains how to buy the right size car stereo by using an online car stereo size database to select your head unit, or by measuring your current head unit.

Use an Online Car Stereo Size Database

Car audio retailers are probably the single greatest source of information about the size and fit for aftermarket car audio components, which makes sense since their customers are far more likely to be satisfied if the components they buy actually fit in their vehicles. Even before the rise of the internet, brick-and-mortar car audio stores typically had size and fit databases that kept track of what size speakers, head units, and other components fit in specific vehicles. Today, that information is always at your fingertips courtesy of the internet.​

Although retailers provide this information with the hopes of making a sale, you are free to use the information from one database and purchase a head unit from whichever outlet you see fit. The key is to plug in the make, model, and year of your vehicle, along with any relevant trim options, and to make note of the head units that the tool says will fit in your vehicle. If the tool shows that double DIN head units will fit, then you can safely buy a double DIN head unit or a single DIN unit with the appropriate dash kit.

Some popular online lookup tools include:

• Crutchfield's Outfit My Car
• Pioneer Electronics Fit Guide
• Sonic Electronix Car Selector

Measure Your Own Head Unit

Fit databases and lookup tools are usually pretty accurate, and you can take most of the guesswork out of the equation by verifying one against another, but physically measuring your head unit is pretty much foolproof. This takes a little more work, and you may have to remove some trim pieces to see exactly what you’re working with, but you’ll have to remove those anyway to replace the head unit.

The most common head unit sizes measure roughly:

• 2” x 7” (50 x 180mm): single DIN
• 3” x 7” (75 x 180mm): one and a half DIN
• 4” x 7” (100 x 180mm): double DIN

If your head unit is 4” tall, then a double DIN head unit will be a direct-fit replacement, while a single DIN or 1.5 DIN head unit will require some type of mounting kit. If your head unit is 3” tall, then you can replace it with a 1.5 DIN head unit or a single DIN unit with the appropriate kit. In some cases, you can also replace a 1.5 DIN head unit with a full double DIN head unit with the right dash kit. And if your head unit measures 2” tall, you’re typically stuck replacing it with a single DIN head unit, unless your vehicle came with a “spacer” or “pocket” that provides enough space to install a 3” or 4” tall head unit.