Wireless Throughput Calculator
Model real Wi-Fi cell throughput with airtime fairness, so slow legacy clients drag the whole cell down the way they do in practice.
Inputs
Usable Cell Throughput
162.5Mbps
Airtime-Weighted PHY Rate
250.0Mbps
Throughput per Client
8.12Mbps
Degradation Caused by Slow Clients
71.1%
Step by step
Values used
PHY rate of modern clients = 866 Mbps; PHY rate of slow legacy clients = 65 Mbps; Airtime share taken by slow clients = 20 %; MAC efficiency after protocol overhead = 65 %; Active clients in the cell = 20 clients
Wireless Throughput
airtime-weighted rate = 1 ÷ Σ(airtime share ÷ PHY rate); usable throughput = that rate × MAC efficiency.
Usable Cell Throughput
= 162.5 Mbps
Airtime-Weighted PHY Rate
= 250.0 Mbps
Throughput per Client
= 8.12 Mbps
Degradation Caused by Slow Clients
= 71.1
How it works
Wi-Fi schedules airtime, not bits, so a client at 65 Mbps occupies thirteen times the airtime of one at 866 Mbps for the same payload. Combining the rates as a harmonic mean weighted by airtime share gives the rate the cell actually achieves, and MAC overhead removes a further third of it. This is why one old handheld can halve a modern cell's throughput, and why removing 802.11b/g data rates is usually the cheapest Wi-Fi performance fix available.
Formula
Wireless Throughput
airtime-weighted rate = 1 ÷ Σ(airtime share ÷ PHY rate); usable throughput = that rate × MAC efficiency.
- airtime share
- Fraction of transmit opportunities a client group consumes
- MAC efficiency
- Throughput left after preambles, ACKs, contention and retries
Frequently Asked Questions
How is Wireless Throughput calculated?
airtime-weighted rate = 1 ÷ Σ(airtime share ÷ PHY rate); usable throughput = that rate × MAC efficiency. Wi-Fi schedules airtime, not bits, so a client at 65 Mbps occupies thirteen times the airtime of one at 866 Mbps for the same payload. Combining the rates as a harmonic mean weighted by airtime share gives the rate the cell actually achieves, and MAC overhead removes a further third of it.
Why does Wireless Throughput matter?
This is why one old handheld can halve a modern cell's throughput, and why removing 802.11b/g data rates is usually the cheapest Wi-Fi performance fix available.
What values do I need to enter?
This calculator takes 5 inputs: PHY rate of modern clients, PHY rate of slow legacy clients, Airtime share taken by slow clients, MAC efficiency after protocol overhead, Active clients in the cell. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.