Calculate the number of concurrent devices a WiFi network can support at target throughput.
Aggregate WiFi capacity is the product of how many channels are used, how wide each channel is, how efficiently the modulation and coding scheme packs bits into each Hz of spectrum, and how many spatial streams MIMO antennas can carry in parallel. Doubling channel bandwidth, spectral efficiency, or spatial streams each roughly doubles capacity, which is why 802.11ax (WiFi 6) achieves far higher throughput than 802.11n primarily through wider channels, denser modulation (1024-QAM), and more spatial streams rather than a faster underlying radio.
Aggregate capacity
capacity = channels × channel_bandwidth × spectral_efficiency × MIMO_streams
Capacity scales linearly with channel bandwidth because a wider channel carries proportionally more subcarriers (in OFDM/OFDMA systems), each capable of carrying the same bits/Hz — doubling bandwidth from 40 MHz to 80 MHz roughly doubles raw capacity, all else equal.
Spectral efficiency is how many bits per second a system can pack into each Hz of bandwidth, determined by the modulation order (QPSK, 64-QAM, 1024-QAM, etc.) and coding rate. Denser modulation packs more bits per symbol but requires a cleaner signal (higher SNR) to be decoded reliably.
Each additional spatial stream can roughly add another multiple of the single-stream capacity, since MIMO transmits independent data streams simultaneously over multiple antennas exploiting multipath — though real-world gains depend on antenna count, spacing, and channel conditions.
No — this is aggregate cell/AP capacity shared across all associated clients and channels. An individual client's achievable throughput depends on its own supported streams/bandwidth, its distance-driven SNR, and contention with other devices on the same channel.