7 Types of headphone jacks – What is the standard headphone jack size?

The headphone jacks on our electronic devices allow us to listen to music and take phone calls. But did you know that there is a difference between the headphone jack size on different devices? If you have a poor quality headphone jack, then it will affect your whole music experience. That is why it is important to know the size of your headphone jack so that you can get a compatible pair of headphones.

In this article, we are going to talk about the most common types of headphone jacks in the electronics world and also tell you, “What is the standard headphone jack size?” After reading this article, you will be able to better understand all about the headphone jack. So let’s dig into the details of them.

What is a headphone jack?


A headphone jack is an audio connector that transmits audio signals from an external device to a pair of headphones (or speakers). A standard headphone jack has a diameter of 2.5mm, and the length varies depending on the type of device it is designed for. The majority of headphones currently use the 3.5 mm (1/8 in) mini phone plug or a 2.5mm jack common on older styles of headphones.

The headphone jack is a very common type of connector used in sound equipment. It is used in audio equipment, including portable media players and mobile phones, amateur radio equipment and many other applications. The connector is sometimes called a phone jack, earphone jack or headphone jack.

Types of headphone jacks – What is the standard headphone jack size - Sound Revealer

The headphone jack was originally designed in 1959 and has since been re-purposed for all the different technologies that have been developed and added to smartphones. It is expected that digital devices will still use this connectivity technology in future devices. Still, the technology inside may change further, although we are unlikely to see it removed any time soon.

A stereo headphone jack was first invented by E.A. Fisher and subsequently refined into the headphone jack we all know today by Jack Baedeker. Since then, it has been used in many radio receivers, televisions and other music devices to keep the wire clutter down. It is now used in every smartphone that is released globally.

How does a headphone jack work?


The headphone jack is a long diameter metal cylinder containing two contacts that make up a simple switch for the signal to pass from your headphones and into your device. The sound produced by your headphones will travel through a cable to reach these metal contacts. When the plug is inserted, and your device detects this, it will send a sound processing signal into the headphone jack. Your headphones will then interpret this signal and produce sound.

The metal contacts inside the jack are attached to plastic washers, which are affixed to a rubber gasket. Together they will each make contact with each other when the plug is inserted into your devices. The rubber gasket will ensure that a watertight seal is formed, ensuring sound processing signals are passed from your devices and to your headphones. 

how does a headphone jack work by Sound Revealer

The main function of the jack is to provide a signal from your smartphone to your headphones, but there are also other things that it can do. Firstly, the jack is connected to a signal amplifier circuit inside your device. This allows for a louder sound produced by your smartphone’s speakers when the jack is plugged in.

The headphone jack can also be used as an antenna for wireless receivers if the device itself doesn’t have one. The extra contact you’ll find in some headphone jacks is an antenna to receive FM radio signals. These are used in conjunction with a chip inside your smartphone to listen to the FM radio without any additional equipment.

Buttons and other controls can also be installed inside the jack. For example, some Android phones have a button that will pause or play music when pressed. This is activated when the jack is inserted and connected to the smartphone.

Types of headphone jacks


There are various types of headphone jacks that are designed for specific uses. Anyone who has a headphone jack on their audio device will know that it comes in many different shapes and sizes. Some are large, some small, some are rectangular, some are square. Some have a button on top, and some do not. The following is a detailed explanation of the most common headphone jack-

1. Lightning Audio Jack- This is the newest type of headphone jack which was introduced in September of 2014. The Lightning Audio Jack is designed for use with Apple devices running iPhone iOS 8.4 or later. On devices that use the Lightning Audio Jack, it can be seen by looking on the bottom of your device and finding a lightning icon on the bottom of your device. This will be a small rectangular jack when you look at it from above, much like the Lightning Charge and Sync Cable.

2. USB Jack- The USB Jack is the most common jack found on devices these days. This type of audio jack is often seen on smartphones, tablets, and other devices. It is also the most popular jack for use with computers. When looking at a headphone jack of this type, it will remind you of the rectangular shape of USB flash drives. 

3. C-Type USB Jack- The C-Type Jack is the most common headphone jack found in various devices. This standard is used by a wide range of devices, including Apple and Microsoft products and many others. The jack is similar in shape to the rectangular USB Jack mentioned above, except it has a small plastic locking clip on one side. Some devices will have two of these jacks for stereo sound. If you have a home stereo system with a headphone jack, chances are it is a C-Type Jack. This jack is also used on most computer microphones and the L R audio ports of some computers.

4. Original 6.35 mm Jack- This is the oldest and most common type of headphone jack in use today. It has been around since 1878 when it was first made for Thomas Edison’s phonograph. It is common because it was used on radios, cassette players, and other devices for many years. This jack is still in use today and can be found on a wide variety of devices. It is commonly seen in home stereos, as well as MP3 players and other personal audio devices. The jack has also been a 6.3 mm jack, the same as the 6.35 mm, except it has a slightly smaller diameter to fit snugly into the same sized hole.

5. 4.4 mm Jack- This type of headphone jack is relatively uncommon and can be found mainly in older devices. This jack was used on some cassette players and other older audio devices. This jack is significantly smaller than the standard 6.35 mm Jack, measuring at under two-thirds of an inch long and 3/16ths of an inch in diameter. Many personal audio devices still retain this type of jack to allow its use with the headphones provided with the device.

6. 2.5 mm Jack- The Sub-Mini 2.5mm Jack is used in various devices, including computers and consumer electronics. This jack is sometimes seen on old MP3 players and other audio devices. The jack itself is very small, and while some headphones will work with this type of jack, they are generally not as common.  

7. 3.5 mm Jack- This type of headphone jack is the most common on smartphones, home stereos, CD players, and other personal audio devices. It is a little over two and a half inches long and resembles the original 6.35 mm jack mentioned above in size, but it is slightly slimmer. The 3.5mm connector has different layer shielding and circular metal shield-like TRS connectors. The Tip carries the audio signal, and the Sleeve holds ground. The Ring carries a reference voltage that lets you know if your audio source is too hot. This means that your audio source is too loud (higher voltage) than the headphones can handle and could damage them.

types of 3.5mm audio jack

There are few types of 3.5mm audio jack in the market depending on the design of the jack and its features. Those are:

  • 3.5mm Jack with Mini Stereo-Mic (TRRS)- This 3.5mm audio jack with a mini stereo mic is very common and can be found on iPad, iPhone, smartphone and other digital products using the Apple iOS system BlackBerry devices and so on. This kind of 3.5mm audio jack comes with four signal lines: Tip, Ring, Ring, Sleeve (TRRS), which are used for stereo audio and microphone signal transmission.
  • 3.5 mm Jack with Mini Stereo (TRS)- This TRS refers to Tip, Ring and Sleeve (TRS) for stereo audio signal transmission, common in computer headsets. It uses both the left and right audio channels for stereo sound, suitable for home theatre systems.
  • 3.5 mm Jack for Mini Mono Audio (TS)- This TS jack is also commonly used in computer headsets. However, it only uses one channel for audio signal transmission, which is the left channel.
  • Dual Mini 3.5 mm Jack (TRS-TRS)- This 3.5mm audio jack is a popular choice for smartphone and tablet accessories and a gaming console, where it can be connected to the audio out port via a Y splitter cable as it provides two signal channels for stereo sound. It is equipped with two TRS jacks, where one end of the jack is used for headphone signal transmission while the other TRS jack is used for headphone microphone signal transmission, which makes the jack very popular in gaming consoles such as PlayStation 3 and Xbox 360.

What is the standard headphone jack size?


The standard headphone jack size depends on other factors, such as the circuit’s voltage, current, or impedance. Before choosing the right size of the headphone jack, you should look at the technical specifications first.

Voltage: With the increment of voltage, the size of the headphone jack decreases. But if we want to know what a smaller jack is for a particular device, we should keep the voltage constant and change only the current that comes out of it.

Current: If we decide to change the current, then the size of the jack increases. Besides this, you can also follow both the ways at once where voltage should be constant and only change the current.

Power: It is the combination of voltage and current which means if we increase the power, then jack size will be larger than before. As we know that most of the devices run on batteries. So if we want to increase the lifespan of these devices, we should choose the right sized jack that should be capable enough to supply the right amount of current, voltage, and power. So if you are making an amplifier circuit, you should select the large-sized jack to deliver more power than a small-sized jack.

Anyway, there is no hard and fast rule which can be followed in all cases. According to their design, it depends upon the manufacturer of your equipment whether they want to fit the large jack or small jack. But as a general rule, we can say that a smaller jack is the best choice for low voltage and small current applications. On the other hand, a large jack is better than a smaller one for high voltage and greater current applications.

The impedance of the circuit: The impedance of the circuit is directly proportional to the size of the jack. This can be determined by measuring the current and voltage produced from the headphone jack. So if you are using the large jack for a low impedance circuit, it will not provide enough current or voltage to your desired equipment. On the other hand, if you use a small jack for a high impedance circuit, it will not provide enough current or voltage to your desired equipment.

Compatibility: There are different jack sizes, and they can be used to connect any audio equipment. The size of the jack can be changed according to different equipment. So it is important to choose the right size, depending on the devices to which the jack will be fitted.

What is the standard headphone jack size

Thus, we can conclude that the standard headphone jack size depends on the factors mentioned above. But most smartphones support the 3.5 mm jack for their audio output. So, it is better to get ready with the 3.5 mm jack for most of our applications.

The next question that arises in your mind is, “What is the standard headphone jack size in millimeters?”

The standard headphone jack size in millimetres can be calculated by counting the number of pins in the 3.5 mm TRS (Tip, ring, sleeve) mini-jack and converting them into millimetres. Using this conversion method, you can easily find the diameter of the 3.5 mm headphone jack in millimetres and other standard headphone jack sizes.

Recently, we have seen that some smartphone manufacturers use a 4-pin Type C connector and the 3.5 mm TRS connector for audio output. The four-pin Type C headphone jack transmits both video and audio signals from the smartphone to the external speakers or headphones. Besides this, it can also transmit data using USB and HDMI protocols as well.

The size of the 4-pin Type C headphone jack is slightly larger than the 3.5 mm TRS connector. All the smartphones in the market are using this type of 4-pin Type C headphone jack. Some high-end smartphones are using two 4-pin Type C connectors simultaneously for connecting to external audio equipment.

So, we can conclude that the standard headphone jack size is 3.5mm, which is the most common in use today and will work with most devices, including some Apple products that have a lightning port instead of an audio jack. However, other sizes besides the typical 3.5 mm size are available, such as 2.5 mm and 6.35 mm headphones jacks for analogue stereo sound systems like those found on airplanes or older video game consoles (Nintendo 64). If you’re not sure what type of connector your device has, it’s best to research before purchasing any new accessories to be safe!

Frequently asked questions (FAQ)


1. How do I know if I have a 3.5 mm jack?

Answer: The 3.5mm headphone jack is shaped like a bullet, and there are a sleeve, pointy Tip, and rings. It has a small centre tip, two rings on the jack’s Sleeve, and a sleeve that tapers off on both sides. You may also see the letters “TRS” written on the jack. The TRS stands for Tip, Ring, Sleeve, so you know the top, middle, and bottom. You can also check the headphone manual for the jack size or test the headphones with a multimeter.

2. Are all 3.5 mm jacks the same?

Answer: NO, they all are not the same. The jacks can be wired differently to fit various purposes. They also have different contact points (for better connection). the contacts may also be pointed or rounded depending on the manufacturer. The speaker connections (small prongs) can be shaped differently and be moved apart or closer to the centre of the jack.

3. Can I use the headphone jack as an audio out?

Answer: Yes, you can use a 3.5mm audio jack as audio out for your computer. However, it will be a mono output. This means that you will not be able to hear sound in both of your headphones. If you only have one set of headphones and a 3.5mm jack, this should be fine.

4. What is the difference between a 2.5 mm and 3.5 mm audio jack?

Answer: A 2.5 mm audio jack is a microphone jack and is generally used for mobile phones or other small handheld devices that require microphones. The 3.5 mm audio jack is primarily used for headphones or headsets that require an analogue audio signal as input. ​It also allows for a microphone to be attached, providing the headset acts as a hands-free device.

The difference between these two jacks is essentially the width and height of the connector. The 2.5 mm jack is smaller and has a thinner profile as it was primarily intended for mobile devices. The 3.5 mm jack is wider and taller, allowing for a headset or headphone to be attached with a microphone for hands-free operation.

The final words (Conclusion)


We hope this blog has helped you understand the types of headphone jacks available to buy today! You can easily use this information to compare and contrast the jacks available, fully understanding what you are buying. We have even added the jack sizes to each type, so you can think before making your purchase! We’ve tried to make it easy to understand for those with a basic knowledge of audio and the technology behind it. If you want to know more about audio or need a little bit of advice on whether the jack you are purchasing is right for your headphones, don’t hesitate to get in touch with us.

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