Most cars came with either a single or double DIN radio, with “double” meaning twice that of single DIN. But there are thousands of vehicles with head units that fall into a strange in-between category. These head units are typically referred to as 1.5 DIN or Din-and-a-half.

What Is DIN-and-a-Half?

“1.5 DIN” or “Din-and-a-half” refers to head units that are sized somewhere between single and double-DIN units. Put simply, they are half the height of double DIN units—or half again the height of single DIN. While dozens of automakers have used the single and double DIN form factors, 1.5 DIN is far less common. It is most often found in GM vehicles, including Chevy, Cadillac, and GMC cars and trucks. In some cases, it can be tough to tell whether or not a vehicle has a 1.5 DIN radio. For that reason, it’s a good idea to measure your head unit or consult a compatibility guide before purchasing an upgrade or replacement.

Car Radio DIN Measurements

While not all car radios conform to a DIN standard, the ones that do are uniform in height and width. Depth may vary, and there’s no standard depth for car radios. However, determining whether you’re working with a 1.5 DIN radio, or one of the other two, is really as simple as measuring the height of the unit. The only way to tell for sure is to remove the bezel around the radio to see how much space is available. If the original radio came with a spacer plate or storage pocket above or below the unit, then there may be enough space to fit a double DIN head unit. In cases where there is enough space to replace a 1.5 DIN radio with a double DIN unit, then there may be a bezel or dash trim piece available for the vehicle. In other cases, the only available option is to fabricate a custom bezel or trim piece. Aftermarket brackets are available for many situations where there is enough space in the dash to upgrade to double DIN. However, you may not be able to find one that works with any given head unit. In dealing with the bezel, you have three options: In many cases, the best option is to call the dealer. If an aftermarket or OEM replacement isn’t an option, then modifying your existing bezel is the next best thing. There are people and companies out there who specialize in exactly this type of work.

Single DIN vs. 1.5 DIN

In most cases, the best option for upgrading a 1.5 DIN head unit is to just install an aftermarket single DIN head unit. Since single DIN is about an inch thinner than 1.5 DIN, replacing the larger of the two with the smaller doesn’t require much extra work. Some aftermarket car radio retailers even offer install kits that come with the appropriate brackets, spacers, or storage pockets to fill the gaps formed by the smaller replacement unit. The last step in our car stereo install guide shows what a single DIN head unit with a storage pocket looks like. Although double DIN head units are great for video, navigation, and other functions, you can find single DIN head units that stack up pretty well. Some single DIN head units have fold-out touchscreens that are just as big as the fixed displays you find on double DIN units, so stepping down from double or 1.5 DIN to single DIN may not be the downgrade some people see it as. The array of options available from aftermarket head units is large.