USB, HDMI and more: the ultimate guide to computer ports

Ports and connectors are not always the first thing you think about when buying a computer, but it's good to know your options and more about the different types of computer ports and their functions. And it can actually make your computer much easier to use.

Choosing a laptop or desktop PC with the right ports for your needs could also save you money down the line, as you won’t have to invest in extra adaptors and docks to get your computer working exactly how you want it. 

All our laptop reviews include details on what ports and adaptors are present on each laptop, and our overall Which? test scores take into account how easy those ports are to use, as well as how fast a laptop’s USB speeds are.

Whatever your budget, our lab tests reveal which models are worth your money and which aren't. See our expert pick of the best laptops

What are the different types of computer port?

Ports you’ll come across on PCs are:

• USB-C: The latest type of USB, expected to replace most ports. Depending on the USB-C connection, it may support DisplayPort which means it can carry a video and audio signal to a monitor. Some laptops now only charge via USB-C. It's reversible, so it doesn't matter which way you plug it in, and is smaller than USB-A. 
• USB-A: Still common and used by lots of accessories like wired mice. It only fits one way round – the trick is to make sure the logo on the connector is facing up as you plug it in.
• HDMI: The most common way to connect a device to a screen. It carries high-quality digital video (HD or 4K) and audio and is supported by most computer monitors and modern TVs.
• Ethernet: You can connect devices that don't have wi-fi to a network. Most desktops and smart TVs will have them, but it's less common on laptops. For super-fast internet, connect a device with an ethernet port to a corresponding ethernet port on your router.
• Micro-USB: A type of USB-B port that was very widely used on Android smartphones before USB-C, and is still used on accessories like some power banks. Since it's so small, it's fiddly to plug it in the right way.
• Mini-USB: This is now very old-school and prett much only for specialist uses.

SD card and micro-SD card readers are also found on multimedia-focused laptops (an SD card socket is better as cheap adaptors let you read micro-SD cards too). 

Some portable-oriented laptops also have a Sim card socket for using with a mobile data plan – these are easily confused with micro-SD card sockets.

Common ports on laptops

Pretty much every laptop continues to have a standard 3.5mm headphones socket – even Apple's famously port-minimal MacBooks. 

Headphone socket aside, some new computers (like MacBook Airs and the MacBook Neo) only have one type of port. If that's the case, it's usually USB-C. 

While others will have around three types – most commonly USB-C, USB-A and possibly HDMI and an SD card socket. So it’s worth spending some time thinking about what you actually need regularly. Do bear in mind that while it's getting harder to find a ports-rich laptop, you can get cheap adaptors for around £10 to gain extra ports.

Need more help with finding what specs you need? See all of our expert advice on laptops 

USB 2.0, 3.0 and 4.0: what’s the difference?

When you're see numbers after a USB socket, no matter whether it's USB-A or USB-C, it's telling you the speed. If you've taken hundreds of holiday snaps on your camera and need to upload these via your laptop, a slow USB socket will leave you waiting around for the file transfer to complete.

No matter what connection speed a device has, it's worth knowing that two devices that have USB connections should be able to talk to one another. As long as you have a cable with the right connections at either end, you’ve won half the battle – it'll work, it just might be as quick as it could be. 

This is because the two devices will simply connect at whatever speed the slowest device is capable of. So if you have a laptop with a USB 2.0 port connected to a hard drive that can deliver speeds up to USB 3.0 standards, your speeds will be limited to that of the USB 2.0 device.

Unfortunately, it's often not easy to tell how fast a USB socket is just by looking at it: you need to check your laptop's specification – either on the manufacturer's website or in the manual. 

Many laptops have faster and slower USB sockets, so it's important you know which the fastest ones are, and use those when you'd benefit from the extra speed. As a simple rule, the bigger the USB version number, the faster the speeds. 

Below, we've explained the differences between USB standards.

Need to know: USB-C as a charging port

The one exception to USBs always playing nice with each other (it'll work, it just might be slow) is with devices that don't have their own power source, but are instead drawing power from the laptop. For example, a desk fan, USB stick, some external hard drives and some digital cameras with batteries removed. 

In these cases, watch out for high power consumption devices, like some hard drives. If you try to use a lower-powered (often slower) USB socket with a high-demand device, it might not be enough to power it. Your USB port needs to meet the minimum power requirements of the device for it to work at all. If you find something doesn't work, try putting in the fastest USB socket.

Similarly, some laptops with a separate charging socket also let you charge via a USB-C socket – but often only if you use the USB-C socket that supports this, and if you're using it with a sufficiently high-watt power adaptor (check your laptop's manual for what it requires).

What USB connection standard do my devices use?

Whether your device’s ports are USB-C, USB-A or a type of USB-B (micro-USB or the rarer mini-USB) or will be relatively obvious from their size and shape. But to find out what speed (connection standard) they use, you’ll need to consult the online manual or spec sheet of your device. 

You might notice that some of your USB ports have different colours and symbols on them. Indeed, there are colour and logo standards for USB ports, but not all computer makers seem to follow these standards. There are also stickers and logos that manufacturers can use, but they don't do this consistently. The only reliable source is a manual or to check the manufacturer's website.

Mid-priced and above laptops generally have USB 3.0 speed sockets or better. Budget laptops (around £500 or less) can still have slow USB 2.0 sockets. For example, Apple's entry-level laptop, the MacBook Neo has: 

• USB 3.1 (up to 10Gb/s) on the back port nearest the hinge 
• USB 2 (up to 480Mb/s) on the second port 

Meaning the USB 3.1 port is more than 20 times faster for data transfer (use the USB 2 socket for charging).

Choosing the correct processor for your computer: Intel, AMD, Snapdragon or Nvidia: CPU and graphics brands explained

What is an HDMI port used for? 

HDMI ports are used to connect PCs to computer monitors or TVs – it's the most common way to hook your PC up with a separate screen. HDMI ports are used to transfer high-quality video (HD or 4K) and audio. If a laptop has only, it will almost certainly only have a single HDMI port.

Some all-in-one (AIO) PCs have two HDMI ports: 

1. One for connecting to a second screen (an output),
2. And one for turning the all-in-one’s screen into a monitor for another device (an input), such as a laptop or games console. In other words, in this case you're effectively using the AIO's screen as if it's just a computer monitor, like hooking up a games console to a TV.

Are there different types of HDMI port?

Yes there are, but HDMI-A is so dominant it's usually just called HDMI. 

There's also the smaller mini-HDMI (C) and micro-HDMI (D). There's also technically an HDMI-B, but it isn't actually used for anything.

As with USB, simply connecting two HDMI devices together should always work in some way or another, but you’ll be limited by the capabilities of the inferior device. This means you may not get the best picture quality that either device is capable of. 

For example, if your laptop’s HDMI port is only capable of delivering a Full HD picture, but your TV is 4K, you’ll be limited to a Full HD resolution when you connect your laptop to that TV. 'Full HD' is a pretty low resolution these days: pixellated text is common even on laptops with such screens, let alone looking at it on a 55-inch TV.

Most modern laptops will support 4K from their HDMI port if they have one. Consult your manual or the manufacturer's online specification sheet to confirm this.

What about older laptops?

If you have an older laptop, it might be a case of trial and error to find out what it’s capable of. But almost every laptop bar the absolute cheapest models from several years ago will be capable of Full HD at a bare minimum – which is serviceable, but you'll see much more detail in a football match if you aim higher.

For more advice, read our explainer on 4K Ultra HD. 

HDMI connections: full-size, mini and micro

While you don’t need to worry too much about HDMI connection standards, it's worth being aware there are different HDMI sizes. Although most laptops and desktops use HDMI-A (which is why it's usually just called HDMI). 

Mini-HDMI (C) is quite widely used in DSLR cameras, camcorders, sat nav systems and some tablets.

HDMI adaptors

Some laptops that don't have an HDMI port and only have USB-C ports may be compatible with HDMI – if you buy a USB-C to HDMI adaptor. We've test all laptops with USB-C ports to find out whether they work with a USB-HDMI adaptor. You can find the results in the Specification section of our laptop reviews.

Cheap adaptors from around £15 are readily available from retailers, including Currys and Amazon. There are also very expensive adaptors, which tend to be aimed at enthusiasts looking for perfect picture quality.

If your computer has an HDMI port but your monitor does not (or vice versa), then you’ll need to buy an adaptor to slot into the connections you do have.

If your monitor doesn’t have HDMI it will likely have either a VGA or DVI port that you can plug the adaptor into. These are older-style prism and long rectanglar ports where the pins are long and prominent surrounded by metal housing, and are often screwed in on each side.

In the case of HDMI to VGA, you’ll need to ensure you also have a spare USB port on your laptop to plug the adaptor into, because these adaptors require a small amount of power to work.

If your computer only has a VGA port but your monitor only has an HDMI port, you will need another form of adaptor that works in reverse to the adaptors mentioned above.

Need a new monitor? See our expert pick of the best computer monitors.

How can I add more ports to my computer?

There are lots of ways to add ports to your computer. As long as you have a USB port to plug it into, you can find an adaptor for practically anything.

If you want to add lots of ports at once, you’ll want to find yourself a dock or hub that includes all the ports you need, be it ethernet, an SD card reader or just even more USB ports.

This is especially handy if you have a dedicated desk with a separate wired mouse and keyboard, but don’t want to have to spend time connecting and disconnecting them every time you want to take your laptop elsewhere. With a hub or dock, you simply have to connect one cable and away you go.

Adaptors come in all sorts of shapes and sizes. If your computer has any USB-C ports, it’s best to buy a USB-C hub as this will allow for the fastest speeds from the devices attached to the dock to the computer itself.

You can also buy computer monitors with USB hubs built-in. This lets you have your bits and bobs connected directly to the monitor, and all you have to do is plug in a single USB cable leading from the monitor to connect them all at once. 

Some USB-C docks will also have HDMI connections, but keep in mind that this will only work if the USB port you’re connecting to supports display connections. Check your laptop manual or the spec sheet on the manufacturer's website first, to see whether it works.

What is a USB port used for?

Whether you’re trying to connect a printer, charge a phone or plug in a mouse, a USB port can do all this. These ports are very much jacks of all trades – in fact, the ‘U’ in USB stands for ‘universal’.

Are all USB ports the same?

In short, no. There are three aspects of a USB port that matter:

• Their physical shape and size, which dictates what connector fits what port.
• The USB connection speed. 
• Extra features, such as the ability to connect to a monitor or accept a charger.

Different ports combine these elements in different ways for reasons of cost and convenience. Below, we’ll first explain the different shapes and sizes you’ll come across, and then the different data speeds.

Different USB shapes and sizes: USB-A, USB-B and USB-C

USB-C: The latest standard

USB-C is the latest generation of USB, and the first USB type that is both reversible (connectors can be inserted either way up) and can appear on both ends of a USB cable. 

They can be used for anything – from charging a laptop or phone, to connecting to a monitor or powering a large external storage device. 

USB-C is the only connector designed to manage speeds up to the USB 4.0 standard, though simply having a USB-C port does not guarantee this. 

USB-C ports have increasingly replaced USB-A ports on modern laptops. Some laptops, including the latest Apple MacBook Airs and the Neo, already exclusively use USB-C ports. 

It’s worth keeping an eye on this if you want your laptop to work with your existing wired devices. Although you can always buy an adaptor if you need a specific port that's not built-in.

USB-A

This is the more traditional USB port that most people will be familiar with – its asymmetrical design means that connectors can only be plugged in one way. 

You’ll find USB-A ports on all desktop computers and most laptops, but not on many non-computing devices – aside from phone chargers that you plug into the wall. 

Most USB cables have a USB-A connector to slot into your computer on one end, and then either some form of USB-B or USB-C that you attach to a phone or other device on the other.

Plus, of course, there are USB accessories where one end is hard-wired into the accessory itself, such as a mouse, keyboard or headset.

USB-B

This type of connector is pretty old-school now, and is almost exclusively found on accessories and handhelds, such as cameras, portable hard drives and printers. There are several versions of USB-B. 

• Full-size USB-B and USB-B 3.0 ports are typically found on printers and older external hard drives. They are different shapes, and USB-B 3.0 cables have a blue connector. 
• Mini USB-B is typically just known as Mini USB, and is found on older handheld devices and accessories such as USB microphones. 
• Micro USB-B is probably the most common USB-B port, and is found on older smartphones and tablets.
• Micro USB-B 3.0 looks like two connectors in one, and is used for devices where higher speeds are important, such as external hard drives. These are becoming less common and are being replaced by USB-C.

Our tough tests reveal the best external hard drives

Charging a laptop with USB-C

Many laptops now come with USB-C ports that are also used for charging, in a similar way that most phones now charge with USB-C. But not all USB-C ports can be used for charging.

There is no hard and fast way of knowing how much power a given USB-C port or cable will accept without checking the product's manual. This is particularly important now as so many laptops can only be charged over USB-C – you will only be able to charge them at decent speeds with the right cable and charger. 

It makes for a somewhat hit-and-miss approach to charging. So while it is handy to be able to charge a laptop with the same cable that comes with your phone, in reality this is likely to be slow unless you have a powerful phone charger.

The upside is if you're running low on battery and only have a USB portable power bank to hand, you can very slowly charge your laptop using it. It's likely the laptop will only gain charge if it's not switched on while you're charging it, unless you have a very powerful battery pack.

The tech specs in our laptop reviews will mention whether a laptop can be charged via USB-C.

What are SD and micro-SD card readers?

Many laptops come with SD card readers or their smaller siblings, micro-SD, built into the frame. The most common use of SD cards is in digital cameras, but they can also be found in other media recording devices such as camcorders and audio recorders.

If your laptop only has an SD card slot but your camera, for example, only takes micro-SD cards, you can buy an SD to micro-SD card adaptor. This is basically an SD card with a slot to pop in a micro-SD card.

If you only have a micro-SD card reader but have a full-size SD card you want to use, you could: 

• Buy a USB to SD card adaptor 
• Or buy a new micro-SD card with an SD card adaptor, so you can easily put the same card into multiple devices.

If your computer has very little storage, you can use your micro-SD card slot as a way of expanding its storage. This could be a good way of storing files you don’t use so often. 

Bear in mind, though, that SD cards are relatively slow compared with built-in computer storage. So shouldn’t be used for storing large, frequently-accessed files or programs.

Which? computing experts have picked out the best laptop deals available now, from budget buys to top-of-the-range models, on brands such as Acer, Samsung and even Apple MacBooks.

What are Thunderbolt ports? 

The ports on MacBooks are described as ‘Thunderbolt / USB 4’. Thunderbolt and USB-C look exactly the same, but they operate slightly differently. 

What this means in practice is that if you’re buying an accessory that uses Thunderbolt connections, such as high-speed external hard drive or a monitor, you should use the supplied cable or a certified Thunderbolt cable. 

If you’re plugging in a regular USB device, you can use either a USB-C cable or a Thunderbolt cable. 

Apple’s support website has further information about USB-C vs Thunderbolt.

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Do I need an ethernet port?

Ethernet ports allow you to connect your PC directly to your router via a cable for a faster and more stable internet connection than is often available over wi-fi. 

Keep in mind that you can’t connect your PC directly to your phone/broadband line – you need a router to make sense of all the data before it is sent to your laptop.

Most laptops don’t have ethernet ports because the connectors required are fairly large. Laptop makers prefer to market thin devices so they often skip this handy port. 

Desktop computers, meanwhile, almost always have ethernet ports.  

Read our guide on the best desktop PC specs for more on what to look for in a desktop computer. Prefer a model that looks good in your home office? See our pick of the best all-in-one PCs.

Is ethernet faster than wi-fi?

Typically, yes. The theoretical maximum speed of most typical ethernet ports is 1,000Mbps (1Gbps), while most wi-fi connections are considerably slower. A wired connection will also have a lower ‘ping’ rate (the time it takes for data to be sent and received), and allow for better gaming and video chatting experiences without lag and stutter.

Wi-fi connections can be affected by all sorts of things, including other electronic devices, your home's walls and the distance to your computer. 

If you’re able to, and your desk happens to be near your router, wiring up your computer to your router is likely to give you the best connection.

Even if your computer doesn’t have an ethernet port, USB-ethernet adaptors typically cost less than £20 and work on any laptop with a USB port. 

Read our wi-fi router reviews to find out all you need to know.