Do WiFi range extenders really work?

How a WiFi extender works

A WiFi range extender, also sold as a WiFi booster or repeater, picks up the WiFi signal from your router and transmits it again, so the signal reaches further than the router manages alone.

“Booster” is a generous word for it. Nothing is boosted. The extender repeats what it hears.

If more than one room has weak WiFi, that is a different job, and a WiFi technician can work out why before you buy anything.

Why an extender halves your speed

Most extenders have one radio. That radio has to listen to the router and talk to your device, and it cannot do both at once. So it takes turns, and every piece of data crosses the air twice. The speed through an extender is about half the speed the extender itself is getting from the router, at best.

Who is on the air, slot by slot

Show the timing

Extender halfway Extender too far away A cable instead

Router 1 2 3 4

Extender 1 2 3 4

Your laptop 1 2 3 4

Time

One radio has to listen to the router and talk to your laptop, and it cannot do both at once. So the two take turns, every block crosses the air twice, and your laptop gets data half the time.

Router 1 2 3 4

Extender 1 2 3 4

Your laptop 1 2 3 4

Time

Put in the dead spot, the extender hears the router faintly. It can only repeat what it receives, so a weak signal in is a weak signal out, still taking turns.

Routerby cable 1 2 3 4 5 6 7 8

WiFi pointon a cable 1 2 3 4 5 6 7 8

Your laptop 1 2 3 4 5 6 7 8

Time

With a cable from the router, the second WiFi point gets its data down the wire. Its radio only talks to your laptop, so the laptop’s lane is full.

That leads to the two complaints we hear most:

• It is slow. Half of a weak signal is not much.
• Devices drop off. If the extender loses the router for a moment, everything connected to it loses the internet. And a phone carried through the house tends to hang on to the extender, or the router, long after the other one would be better.

What decides whether an extender works

1. Where it is. Halfway between the router and the dead spot, where the router’s signal is still strong. Not in the dead spot.
2. What is in the way. Brick and concrete walls, a floor between storeys, mirrors and metal all cut the signal the extender has to work with.
3. The extender itself. A dual-band or tri-band model, which can use one band to talk to the router and another to talk to your devices, loses less speed.
4. How much you ask of it. Browsing in a spare room is fine. Three people streaming through it is not.

So are extenders effective?

For the right job, yes. One room, a bit too far from the router, light use: an extender in the hallway outside it will usually do.

For the wrong job, no. An extender cannot make a weak signal strong, it cannot serve a whole floor, and it adds a second thing to go wrong. A lot of the “my WiFi keeps dropping out” calls we take turn out to involve an extender.

Extender, mesh or cable

WiFi extender, mesh system and cabled WiFi point compared

Compared on	WiFi extender	Mesh system	Cabled WiFi point
How it gets its signal	Repeats the router's WiFi	Units talk to each other, by WiFi or by cable	A network cable from the router
Speed in the far room	About half of what the extender receives	Good, and best when the units are linked by cable	Full speed
Coverage	One room or area	The whole house	Wherever a cable can be run
Moving around the house	Devices cling to one or the other	Devices are handed from unit to unit	Handed over, on a matched system
Setting up	Simple	Simple, by an app	A cable has to be installed
Cost	Cheapest	Dearer	The cable is the cost
Network name	Often a second name	One name	One name

When to choose an extender

• The router is in a good, central spot, and one room misses out.
• You want a quick fix without changing anything else.
• The use in that room is light.

When to choose mesh

• Several rooms or a whole floor have poor signal.
• The house is long, two-storey, or has solid walls.
• People walk around on video calls, or there are a lot of smart devices.

If you are choosing a system, our mesh and modem picks say what to look for.

Mesh has its own rules about where the units go. See how to boost a mesh WiFi signal and why mesh WiFi keeps disconnecting.

When a cable beats both

• The router is in the wrong place to begin with, such as the garage or a front bedroom, because that is where the NBN box was put. Extending a signal that starts in the wrong spot is working uphill. A cable run from the NBN box to a router in the middle of the house fixes the cause.
• A granny flat, a studio or a shed. WiFi does not cross a backyard and a brick wall reliably. A cable does.
• A home office or a games console. Anything that must not drop out belongs on a cable.
• Concrete between floors. Mesh units cannot talk through a slab. Linked by cable, they work perfectly.

A cable is more work on the day and no work afterwards. Get a rough price for the cable run, or see how to set up a wired network at home.

Are WiFi extenders safe?

Yes. An extender is a small WiFi radio, the same kind as the one in your router. A mobile signal booster is a different thing, and the ACMA says those are banned. The thing to look after is security, because an extender is another way onto your network.

• Give its WiFi a strong password, the same standard as your router’s.
• Use WPA2 or WPA3 security.
• Change the admin password it came with.
• Keep its firmware updated, and replace one that no longer gets updates.

Can you use more than one extender?

You can, if each one connects straight to the router: one for the room at one end, one for the room at the other.

Do not chain them. An extender fed by another extender halves the speed twice. If the house needs two or three, that is the sign it has outgrown extenders.

Test before you buy anything

Check your speed first Test on WiFi beside the router, then in the room with the problem. If it is fast at the router and slow in that room, it is coverage. If it is slow at the router too, no extender will help.