5 GHz Channel Planner
Count the non-overlapping 5 GHz channels available at your chosen width with or without DFS, and check the reuse it allows.
Inputs
Non-Overlapping Channels
12
Radios Sharing Each Channel
2.00
Co-Channel Neighbours per Radio
1.00
Spectrum in Use
480MHz
Assessment
Acceptable reuse for a typical enterprise floor
Step by step
Values used
Channel width = 40 MHz; DFS (UNII-2 / UNII-2e) channels permitted = Yes; 5 GHz radios in the coverage area = 24 radios
5 GHz Channel
channels = usable 5 GHz spectrum ÷ channel width, counted separately for the DFS and non-DFS sets; radios per channel = radios ÷ channels.
Non-Overlapping Channels
= 12
Radios Sharing Each Channel
= 2.00
Co-Channel Neighbours per Radio
= 1.00
Spectrum in Use
= 480 MHz
Assessment
= Acceptable reuse for a typical enterprise floor
How it works
Excluding DFS leaves only UNII-1 (36–48) and UNII-3 (149–165), which is nine 20 MHz channels and no 160 MHz channel at all. Adding the UNII-2 and UNII-2e radar bands roughly triples the count, at the cost of radar-detection channel changes. Channel reuse is what determines whether adjacent APs cooperate or compete, and avoiding DFS to dodge radar events is exactly what starves a dense floor of spectrum.
Formula
5 GHz Channel
channels = usable 5 GHz spectrum ÷ channel width, counted separately for the DFS and non-DFS sets; radios per channel = radios ÷ channels.
- withDfs
- 25/12/6/2 channels at 20/40/80/160 MHz with DFS
- withoutDfs
- 9/4/2/0 channels using only UNII-1 and UNII-3
Frequently Asked Questions
How is 5 GHz Channel calculated?
channels = usable 5 GHz spectrum ÷ channel width, counted separately for the DFS and non-DFS sets; radios per channel = radios ÷ channels. Excluding DFS leaves only UNII-1 (36–48) and UNII-3 (149–165), which is nine 20 MHz channels and no 160 MHz channel at all. Adding the UNII-2 and UNII-2e radar bands roughly triples the count, at the cost of radar-detection channel changes.
Why does 5 GHz Channel matter?
Channel reuse is what determines whether adjacent APs cooperate or compete, and avoiding DFS to dodge radar events is exactly what starves a dense floor of spectrum.
What values do I need to enter?
This calculator takes 3 inputs: Channel width, DFS (UNII-2 / UNII-2e) channels permitted, 5 GHz radios in the coverage area. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.