When Wi-Fi feels slow, the problem is in one of four places: the device, the Wi-Fi link, the router, or your internet connection itself. Three quick tests tell you which:
| Test result | Most likely cause | Go to |
|---|---|---|
| Only one device is slow | That device | Branch D |
| Slow even on a device plugged into the router | Your internet, modem or router port | Branch A |
| Fast near the router, slow further away | Coverage | Branch B |
| Slow over Wi-Fi even right next to the router | Band, interference, settings or old gear | Branch C |
This diagnosis is Router Academy’s method; each fix below cites the vendor guidance it relies on.
First: restart the modem and router
It’s the cheapest fix, and both Apple and Microsoft suggest it. Microsoft’s steps are to unplug the router and the modem, wait at least 30 seconds, then plug the modem back in first and the router after it. If speed comes back and stays back, you’re done. If the slowness returns, continue.
Test 1: is it one device or all of them?
Try another device in the same spot. Apple’s guidance is a good rule: if other devices can connect, the router and network are working. If only one device is slow, skip to Branch D.
Test 2: wired versus Wi-Fi
Run a speed test on a computer plugged into the router with an Ethernet cable, then run the same test over Wi-Fi standing next to the router.
Branch A: slow even when wired
The bottleneck is before your Wi-Fi:
- Your router’s internet port. A router can’t pass more than its internet (WAN) port allows. gFiber, for example, recommends a 1 Gbps WAN port for its 1 Gig plan and a 10 Gbps WAN port for its multi-gig plans. If your plan is faster than your router’s port, the router is the limit.
- Two routers in a row. A router plugged into a gateway that is also routing can cause problems; see Double NAT.
- The connection itself. If a device plugged straight into your modem or gateway is also slow, contact your provider. Modem vs router vs gateway helps you tell which box is which.
Branch B: fast near the router, slow further away
This is a coverage problem. Microsoft’s advice for slow Wi-Fi is to keep the device close to the router and free of obstructions. If that isn’t practical, Wi-Fi dead zones walks through placement, bands, walls and when to add mesh or an extender.
Branch C: slow over Wi-Fi even close to the router
Work through these in order:
- The band. 2.4 GHz reaches furthest but is crowded by older devices and has only three 20 MHz channels. If your device supports 5 GHz or 6 GHz, try connecting on those near the router. See 2.4 GHz vs 5 GHz vs 6 GHz.
- Interference. TP-Link lists microwaves, Bluetooth devices and USB 3.0 devices as sources of 2.4 GHz interference. Microsoft suggests changing the router’s wireless channel to reduce interference.
- Router settings. Apple publishes recommended settings for routers: WPA3 (or WPA2/WPA3 transitional), one network name for all bands, automatic firmware updates enabled, 20 MHz channels on 2.4 GHz, and automatic or all channel widths on 5 GHz and 6 GHz.
- Firmware. Apple also advises updating the router to its latest firmware.
- Old hardware. If the router or the device is several Wi-Fi generations old, its maximum speed may simply be lower than your plan. Wi-Fi standards explained shows what each generation can do, and How to choose a Wi-Fi router helps if it’s time to replace it.
Branch D: only one device is slow
The problem is that device. On Windows, Microsoft advises checking for the latest Wi-Fi adapter driver through Windows Update. Also check that it’s connecting on the band you expect and isn’t far from the router. If it also keeps dropping its connection, see Wi-Fi keeps disconnecting.
If that sounds like your problem, Bufferbloat explained shows how to test for it and fix it.