Why Is My Wi‑Fi So Slow? 12 Causes and How to Fix Each

"The Wi‑Fi is slow" can mean a dozen different problems: your internet plan, the router, the radio band, the walls, a neighbour's network or a single misbehaving device. The trick is to narrow it down before changing anything. Work through the causes below in order — the first ones are the most common and cost nothing to fix.

Your internet connection is the bottleneck, not Wi‑Fi

Start by separating the two. Plug a laptop into the router with an Ethernet cable (or stand right next to the router) and run a speed test. If you get roughly the speed you pay for, the line is fine and the problem is Wi‑Fi coverage. If the wired result is also low, restart the modem/ONT and router; if it stays low, contact your provider — no router setting will fix a slow line. Also remember that Wi‑Fi can never be faster than your plan: on a 100 Mbit/s plan, 90 Mbit/s over Wi‑Fi is a good result.

The router needs a restart

Routers run for months without a reboot, and memory leaks, overheating or a stuck connection to the provider can slow them down. Unplug the router (and modem, if separate) for 30 seconds, plug the modem in first, wait until it's online, then the router. If you need to do this every few days, the router may be failing or overheating.

You're too far away or behind too many walls

Wi‑Fi gets weaker with every metre and every wall. Concrete, brick, metal, mirrors and water (aquariums, boilers) are the worst. If speed is fine in the router's room but poor two rooms away, placement is the likely cause. Move the router to a central, high, open spot — see where to put your Wi‑Fi router for the detailed rules.

You're on the 2.4 GHz band

2.4 GHz reaches further but is slower and much more crowded; 5 GHz (and 6 GHz on Wi‑Fi 6E/7) is far faster at short to medium range. If your router uses separate network names, connect phones, laptops and TVs to the 5 GHz one when you're reasonably close. If it uses one combined name (band steering), the router should choose for you, but older devices sometimes cling to 2.4 GHz. Our 2.4 GHz vs 5 GHz guide explains which devices belong on which band.

Interference from neighbours' networks

In apartment buildings, dozens of networks compete for the same channels. A Wi‑Fi analyser app shows how crowded each channel is. On 2.4 GHz, stick to channels 1, 6 or 11 and pick the least busy; on 5 GHz, there are many more channels, so "auto" usually works, but trying a different one can help. Using 20 MHz channel width on 2.4 GHz is often more stable than 40 MHz in crowded buildings.

Other electronics are getting in the way

Microwave ovens, some cordless phones, baby monitors, wireless video senders and even USB 3 hubs can disturb 2.4 GHz Wi‑Fi. If the network slows down only when the microwave runs, that's your answer: move the router away or use 5 GHz.

Too many devices are using the connection at once

Every device shares the same airtime and the same internet line. A 4K stream, a game download, cloud photo backup and a video call at the same time can saturate a modest plan. Check the router app for devices using lots of data, pause big downloads and backups, and consider QoS (traffic prioritisation) if your router offers it. Smart home gadgets use little bandwidth, but dozens of them on an old router can still strain it.

The router is old

A router from 2015–2017 with Wi‑Fi 4 (802.11n) or early Wi‑Fi 5 may simply not keep up with today's plans and device counts. If your plan is faster than about 300 Mbit/s, or you have many devices, a Wi‑Fi 6 or newer router is a real upgrade. The provider's free router is also often the weakest link — you can usually add your own router behind it. See our Wi‑Fi 7 explainer to decide how new you need to go.

The router's firmware is out of date

Firmware updates fix bugs, security holes and sometimes performance problems. Check the router app or web interface and turn on automatic updates if available — our guide on how to update router firmware shows how.

The problem is one device

If only one phone or laptop is slow, the network is probably fine. Turn the device's Wi‑Fi off and on, "forget" the network and reconnect, update the operating system and Wi‑Fi drivers (on Windows, from the laptop maker's site), and disable any VPN to test. An old laptop with a Wi‑Fi 4 adapter or a single antenna will always be slower than a new phone in the same spot.

A VPN, proxy or security software is slowing things down

VPNs route traffic through a distant server, which adds delay and can cap speed. Test with the VPN off. Some antivirus "web protection" features and ad-blocking DNS services can also add delay; temporarily disabling them tells you quickly whether they're the cause.

Your home is too big for one router

Large homes, several floors, L‑shaped layouts or thick walls can defeat even a well-placed router. If one area is always slow, add hardware: a mesh system or a second access point connected by Ethernet works much better than a basic extender. Compare the options in Wi‑Fi extender vs mesh and our mesh Wi‑Fi buying guide.