Trade Wi-Fi channel width against PHY rate, noise-floor penalty and how many non-overlapping channels remain for reuse.
Doubling the channel width doubles the subcarrier count and therefore the PHY rate, but it also doubles the received noise power, which costs 3 dB of link budget per doubling and halves the number of channels available for reuse. Wide channels are the single most over-used Wi-Fi setting: 80 MHz on a dense floor buys headline speed on one AP and co-channel interference on every other one.
Channel Width
PHY rate = data subcarriers × bits per subcarrier × coding rate × spatial streams ÷ 13.6 µs symbol time; noise penalty = 10·log10(width ÷ 20).
PHY rate = data subcarriers × bits per subcarrier × coding rate × spatial streams ÷ 13.6 µs symbol time; noise penalty = 10·log10(width ÷ 20). Doubling the channel width doubles the subcarrier count and therefore the PHY rate, but it also doubles the received noise power, which costs 3 dB of link budget per doubling and halves the number of channels available for reuse.
Wide channels are the single most over-used Wi-Fi setting: 80 MHz on a dense floor buys headline speed on one AP and co-channel interference on every other one.
This calculator takes 5 inputs: Channel width, Spatial streams, Bits per subcarrier (modulation), Coding rate, MAC efficiency after overhead. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.