Back in the day, if you can believe it, people didn’t have the luxury of listening to their own playlist. Instead, they were stuck listening to the same tunes on the radio if only one radio was shared. They often took up a lot of real estate and buying one for yourself, as a kid, was not an option.

But then, something magical happened. Radios got smaller, more compact, cheaper, and could even play tapes. More importantly, a headphone jack was built right into the system. You could listen to your favorite music without sharing it with someone else. In fact, one of the most popular devices to come built with a headphone jack was none other than Sony’s Walkman.

However, headphone jacks are not one size fits all. You have all kids that serve different purposes. Two types, 3.5mm and 2.5mm jack, are often cited as the most used. The question is: what’s the difference between 3.5mm and 2.5mm?

The First Difference: Size

Placing both a 2.5mm and 3.5mm jack side by side and you’ll quickly notice the difference in size. A 3.5mm jack is going to be nearly 50% bigger. After all, “3.5” also refers to the size of the connector itself. It has a whole 1mm over it.

With that size also comes some added durability. A 2.5mm connector is still sturdy—it’s still metal and tough to bend—but the added girth on a 3.5mm provides a stronger frame.

The Second Difference: Shape

The next feature you might notice is the shape of the jack itself. Notice the ridges? You have the tip, the “rings,”—often colored black—and the “sleeves.” The sections in between the rings are known as sleeves. At the base of the jack is the “ground.”

Each ring provides a different function, supporting audio, headsets, audio channels, and other possibilities. For example, if you have a device, say a two-way radio, and you need to add a headset. Sometimes 2.5mm jacks come with an additional ring to provide support for said headset.

The Final Difference: Usage

This may come as a shock, but due to the size and shape of the 3.5mm and 2.5mm jack, they’re used for different devices. Didn’t see that coming, did you?

With that said, 3.5mm is way more common; 2.5mm is heading out the window. Smartphones? 3.5mm. Tablets? 3.5mm. Computer? 3.5mm. Console controllers? 3.5mm. Most devices that are built with a headphone jack are going to use 3.5mm. Anything sporting a 2.5mm plug tends to be dinosaur equipment like cordless phones and two-way radios. However, important devices like hearing equipment, may have a 2.5mm connector.

More in Common Than You Think

Aside from shape and size, 3.5mm and 2.5mm jacks are practically identical. Sure, 3.5mm is almost 50% bigger, but functionally speaking, they’re the same. In fact, you can find adapters for both 3.5mm and 2.5mm if you want to convert one to the other, 3.5mm to 2.5mm and vice versa. Quality, on the other hand, is an entirely different story.

Bottom Line

While 3.5mm is more commonly used over the smaller variant, there’s no denying that 3.5mm has a limited shelf life. Advances in Bluetooth are only slowly pushing it away from the spotlight until it too meets the same fate as 2.5mm. And really, it comes down to convenience.

Do you want to deal with an annoying set of wires or would you rather pop a few wireless earbuds in and get the same effect? Everything is moving to wireless these days, and headphones aren’t immune to the push.