2.4 GHz
2.4 GHz generally travels farther through a typical home than higher-frequency Wi‑Fi and has broad legacy-device compatibility. It also has less clean channel capacity and shares spectrum with many non-Wi‑Fi devices.
5 GHz
5 GHz offers much more channel capacity than 2.4 GHz and is widely used by Wi‑Fi 5, Wi‑Fi 6 and Wi‑Fi 7 devices. Range through obstacles is often shorter than 2.4 GHz, but the additional spectrum can improve practical capacity.
6 GHz
Wi‑Fi 6E and Wi‑Fi 7 can use 6 GHz spectrum where regulators permit it. The band adds newer, less legacy-congested spectrum and can support wide channels, but device support and permitted channel/power rules vary by country.
Automatic band steering
Many routers use one network name and decide which band a device should use. That can simplify roaming, but the client device also makes its own radio decisions and may not always choose the band you expect.
Frequency is only part of coverage
Transmit power, antennas, walls, floor construction, interference, channel width and the client device all affect usable coverage. A “6 GHz router” does not make every existing device use 6 GHz.