Wi-Fi Bands and Channels

Wi-Fi uses radio bands, and each band is divided into channels. Your network sits on one, and so do your neighbours’.

The bands

• 2.4 GHz reaches furthest and goes through walls best, but it’s slow and crowded: it has room for only three channels that don’t overlap, 1, 6 and 11, and microwaves and Bluetooth use the same band.
• 5 GHz is much faster and has many more channels, but reaches less far.
• 6 GHz, with Wi-Fi 6E and 7, is fastest and nearly empty, with the shortest reach. Only newer devices use it.

Sharing a channel

Networks on the same channel take turns to send. It’s like a conversation in a crowded room: everyone gets through, just less often. Networks on overlapping channels, say 3 and 6, are worse: they can’t hear each other well enough to take turns, so they talk over each other. That’s why picking 1, 6 or 11 on 2.4 GHz matters.

Channel width

A network can bond channels together, 40, 80 or 160 MHz wide instead of 20, to go faster. Wider is faster when the air is quiet, and overlaps more neighbours when it isn’t. On 2.4 GHz, 20 MHz is almost always best.

DFS channels

Some 5 GHz channels are shared with weather and airport radar. A router on one of these DFS channels must leave it at once if it hears radar, which makes it pause briefly. They’re often the quietest channels, and worth it where there’s no radar nearby. When Wi-Fi Networks recommends one, it says so.

Related

• Wi-Fi Networks, which recommends a channel.
• Wi-Fi signal.