How to Make Your New Car Radio Fit

Tips to make sure your car radio replacement fits the space in your dash.

Two men in front of a van with a measuring tape

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There are a handful of reasons why a new car radio may not fit correctly. In some cases, you can use a car radio fit kit to install a radio that's not sized correctly for your head unit. But there are limitations. For example, while you can use an installation kit to replace a 2 DIN car radio with a 1 DIN car radio, the opposite is not always possible. Also, some aftermarket car stereos won’t fit into certain installation kits, and other combinations can make your dashboard look messy and cluttered.

When a New Car Radio Doesn’t Fit

Factory car stereos come in all shapes and sizes, but there are three common form factors for aftermarket units that are all based on a single DIN standard. The DIN standard for car radios specifies a height of 50mm and a width of 180mm, with no mention of depth. Measured in inches, that's roughly 2 inches tall by 7 inches wide.

The other two common head unit sizes are also taken from the DIN standard. The largest is 2 DIN, which is 4 inches tall and 7 inches wide. The less common 1.5 DIN measures roughly 3 inches tall by 7 inches wide.

Looking at the three common car radio sizes, it’s easy to see how you could end up with some problems. Head units built to the 2 DIN or 1.5 DIN specifications simply won’t fit in a slot meant for a 1 DIN head unit, and trying to put a 1 DIN stereo in the space afforded a 2 DIN unit will leave a large gap.

Solving Car Radio Fit Problems With Installation Kits

In most cases, the solution to a new car radio that doesn’t fit is a car stereo installation kit. Unlike aftermarket head units, which are platform agnostic and designed to work in a wide variety of cars and trucks, each installation kit is purpose-built for a very specific range of makes or models.

The classic use for a car radio installation kit is to allow a 1 DIN aftermarket radio to fit into a dash that came with a 2 DIN or 1.5 DIN factory stereo. This type of kit includes a slot and mounting hardware that will fit any 1 DIN aftermarket radio, while also fitting perfectly into the dash of the specific make, model, and year of your vehicle. In many cases, this type of kit will also include a storage pocket to make use of the extra space.

When a Car Radio Won’t Fit in an Installation Kit

Despite the fact that aftermarket radios conform almost uniformly to 1 DIN, 1.5 DIN, or 2 DIN dimensions, there are circumstances where an aftermarket head unit doesn’t fit a correctly sized installation kit. This is usually due to the slight difference between the actual DIN standard, which is measured in millimeters, and the accepted US standard, which is given in inches.

If an installation kit from one manufacturer doesn’t work with your new head unit, there is a good chance that a kit from a different manufacturer will. This situation is uncommon, but if the make and model of your car is popular, you may need to do some model-specific research to learn if there are any likely sizing problems.

In some cases, it’s possible to make an aftermarket head unit work with an ill-fitting install kit by shaving off a tiny bit of material with a Dremel tool. But that goes above and beyond what most people are willing to undertake when installing a new car radio.

When a Car Radio Fits the Installation Kit but Doesn’t Look Clean

One issue that people often run into when using an installation kit is that, depending on the design of the head unit, the final installation may look messy or cluttered. The issue here is that aftermarket car stereos are typically designed to use a bezel, which overlays the head unit's sizing gaps and electronic components.

When you install an aftermarket head unit into a dash slot using the included cage, the face of the radio sticks out far enough to snap the bezel on. This results in the type of aftermarket installation that, while aesthetically irregular, manages to hide any exposed gaps.

When you install an aftermarket head unit with a dash kit, the head unit is often bolted to the kit via ISO mounts. This can result in a much cleaner look if the factory bezel is consistent. However, there are many situations where the factory bezel doesn’t cover the gaps between the mounting kit and the aftermarket radio, which can result in a less than attractive final product.

In most cases, an ISO-mounted head unit will not stick out far enough for the aftermarket bezel to be installed and snap on securely. Depending on the specifics of the vehicle, it may be possible to loosen the mounting bolts and slide the radio out far enough to attach the aftermarket bezel or slide it back flush with the dash so that the gaps are less obvious.

Making Sure a Car Radio Will Fit

If you’ve already bought a new car radio and are unable to return it, then you may be stuck trying to find a way to make it fit. For those who haven’t yet purchased a new head unit, there are a few ways to make sure that the new radio will fit. In many cases, the easiest way to make sure it fits is to measure the old car radio.

Since most radios are either 1 DIN, 1.5 DIN, or 2 DIN, you may be able to simply eyeball the measurement. To make sure, use a tape measure to confirm the size. If it’s about 2 inches tall, then it’s a 1 DIN, if it’s about 3 inches tall it’s a 1.5 DIN, and if it’s about 4 inches tall it’s a 2 DIN.

If you’re buying a new car stereo as a gift and don’t have access to the vehicle, or if the dash is designed in such a way that it’s difficult to tell at a glance how tall the stereo is, then the safest way to make sure you buy the right size unit is to consult a fit guide.

Most car stereo retail stores can help you with this. Such information is also available through retailers like Crutchfield and Sonic Electronix. Using a fit guide from a reputable online retailer doesn’t require you to actually buy from that retailer, so it’s a good way to get an idea of what will actually fit in your car regardless of where you end up buying your new head unit from.