What is a WiFi dongle?
A WiFi dongle is a small USB stick that connects a device to the internet without a cable. The trouble is that the same name covers two different gadgets, and buying the wrong one is an easy mistake to make.
The first is a USB WiFi adapter. It adds wireless networking to a computer that has none, or has a weak one, so it can join a WiFi network that already exists. It does not create internet by itself.
The second is a mobile broadband dongle, sometimes called a 4G or 5G WiFi dongle. It holds a SIM and uses a mobile signal to create its own connection, much like your phone does.
The word “dongle” has never sounded serious, but the money is. Knowing which type you need is the difference between a cheap fix and a bill you did not plan for.
What does a USB WiFi dongle do for your computer?
A USB WiFi dongle gives a desktop PC or an older laptop a way to join your home WiFi. HomeWire, a UK home networking site, describes it as a tiny radio and antenna that does the same job as the WiFi built into a phone or laptop.
You plug it in, install a driver if your computer asks for one, and connect to your network as normal. This type of dongle needs an existing connection, such as your home router. It will not give you internet in a place where you have none.
If you are shopping for one, HomeWire suggests looking at four things:
- The WiFi standard, which should match what your router supports. It suggests at least WiFi 5, and WiFi 6 if you can, but only WiFi 6E if your router supports that too.
- Dual band support, meaning both 2.4GHz and 5GHz. It treats a 2.4GHz-only dongle as poor value.
- The USB version, because a fast dongle in a slow USB port gets held back. Speeds above roughly 400Mbps need a USB 3.0 port.
- The antenna, since a bigger or extendable one can reach further from the router, while small “nano” models are neater but shorter range.
It also makes a fair point worth repeating. A dongle fixes a weak adapter on one device. It cannot fix a weak signal reaching that part of the house, so if the WiFi itself is patchy, our guide to powerline adapters covers another way to extend your coverage.
What is a 4G or 5G WiFi dongle?
A 4G or 5G WiFi dongle is a mobile broadband device. Which? describes it as a small device that connects to your gadgets through USB or WiFi, using the same signal as a smartphone instead of a phone line.
Which? says each of the big four networks, EE, O2, Vodafone and Three, offer 4G and 5G mobile broadband, either through a dongle or a home router. Contract lengths run from one month up to two years, and data limits can be as low as a few gigabytes.
On cost, Which? said in April 2026 that you could pay as little as around £10 a month for a limited data plan, and that around £20 to £30 a month is more usual for unlimited data, with 5G often costing more. Those are Which? estimates from earlier this year, so check the plan in front of you.
On speed, Which? reports that OpenSignal data had the big four typically achieving 4G download speeds as high as 46Mbps. That is the top of what was typical, not a floor, so plan for less rather than more.
Key takeaways
- A USB WiFi dongle adds WiFi to a computer. It needs a router or hotspot to connect to.
- A 4G or 5G WiFi dongle has a SIM and creates its own connection.
- Mobile broadband speeds depend on your local signal, and data caps can bite.
- Check how many devices a mobile WiFi dongle can serve before you buy. Many handle only one at a time.
Can a WiFi dongle replace your home broadband?
It can, but only in the right situation. Which? calls a mobile dongle a flexible and affordable alternative if you are struggling to get a reliable fixed line, and it works best with a dependable 4G or 5G signal.
TechRadar takes a more cautious line. Its guide says a dongle is not a great choice if lots of people are using the internet, because many dongles are limited to one device at a time. It also warns that a poor mobile signal in your area means slow or patchy service.
Which? makes the same point from the other direction, saying dedicated mobile routers can handle many more devices and traffic than a dongle or tethering can. Neither source gives a device count for dongles themselves, so check the product listing for the limit before you commit.
Data is the other catch. TechRadar notes that many providers cap data on dongles and advises checking with the provider before you order. Which? gives an example of heavy use, saying an hour of HD Netflix uses around 3GB, so a small allowance can disappear quickly.
A mobile dongle can be a useful stopgap if you are waiting for a line to be installed or have just moved. Our guides to the broadband installation wait and new build broadband cover those situations in more detail.
How do you choose the right WiFi dongle?
Start by deciding what job you want it to do. If your computer simply cannot find your home WiFi, you want a USB adapter. If you need internet where you have no line, or while you wait for one, you want a 4G or 5G WiFi dongle with a SIM.
For a mobile dongle, work through the practical questions in this order. How strong is the signal where you will use it? How much data will you really use? How many devices need to connect? And how long is the contract?
The data question trips people up. Our guides to mobile hotspot data and data only SIM deals explain how allowances work and what happens when you go over.
If you find yourself reaching for a dongle because your home broadband keeps failing, that may be the real problem. This is the Do-Nothing Default again: it is easy to put up with a poor line for years. A quick comparison shows what is on sale at your address, and the price depends on your usage and your postcode. Roo handles the digging.
Frequently asked questions about the WiFi dongle
- What is a WiFi dongle used for?
- A USB WiFi dongle adds wireless networking to a computer. A 4G or 5G WiFi dongle uses a SIM to create its own internet connection.
- Does a WiFi dongle give you internet without a router?
- A USB WiFi adapter does not, because it needs an existing network to join. A mobile broadband WiFi dongle does, because it has a SIM and uses a mobile signal.
- How much does a mobile WiFi dongle cost a month?
- Which? said in April 2026 that you could pay as little as around £10 a month for limited data, and around £20 to £30 for unlimited data. Prices change, so check the plan itself.
- Can several devices use one WiFi dongle?
- It depends on the device. Many dongles are limited to one device at a time, while dedicated mobile routers handle more. Check the listing before you buy.
- Is a WiFi dongle as fast as fibre broadband?
- Usually not. Which? reports OpenSignal data putting typical 4G download speeds for the big four as high as 46Mbps, and says 4G is very unlikely to match fibre. 5G can be faster where coverage is strong.
Sources
- Which?, 4G and 5G home broadband and wi-fi dongles explained, 14 April 2026. The around £10 a month for limited data and £20 to £30 for unlimited, the big four networks offering 4G and 5G mobile broadband, contract lengths from one month to two years, the OpenSignal figure of 4G download speeds as high as 46Mbps, the 3GB per hour of HD Netflix, and that dedicated routers handle more devices and traffic than dongles or tethering.
- TechRadar, How to use a broadband dongle, 23 May 2024. That many dongles are limited to one device at a time, that a dongle is a poor choice where lots of people use the internet, that many providers cap data on dongles, and the effect of a weak mobile signal.
- HomeWire, WiFi dongle explained. The description of a USB dongle as a tiny radio and antenna, the four buying checks on WiFi standard, dual band, USB version and antenna, and the point that a dongle cannot fix a weak signal reaching part of the house.
Checked 29 October 2026.
