Calculator Inputs
Example Data Table
| Scenario | Band | Channel | RSSI | Noise Floor | Utilization | Co-Channel | Adjacent | Retry Rate | PHY Rate |
|---|---|---|---|---|---|---|---|---|---|
| Small Office | 5 GHz | 36 | -58 dBm | -92 dBm | 42% | 2 | 1 | 8% | 433 Mbps |
| Apartment Block | 2.4 GHz | 6 | -67 dBm | -88 dBm | 74% | 6 | 4 | 18% | 144 Mbps |
| Modern Campus | 6 GHz | 37 | -61 dBm | -95 dBm | 31% | 1 | 0 | 4% | 1201 Mbps |
Formula Used
This calculator combines signal quality, airtime use, retry behavior, and overlap pressure into a practical spectrum score.
1) Signal-to-Noise Ratio
SNR = RSSI - Noise Floor
2) Overlap Risk
Overlap Risk = Co-Channel × 14 + Adjacent × 10 + Width Penalty + Band Penalty + Environment Penalty + Density Penalty
The result is capped between 0 and 100.
3) Congestion Index
Congestion Index = Utilization × 0.55 + Retry Rate × 0.90 + Overlap Risk × 0.55 + SNR Penalty
SNR Penalty = max(0, 28 - SNR) × 2.1
4) Channel Health
Channel Health = 100 - Congestion Index
5) Throughput Efficiency
Throughput Efficiency % = SNR Factor × Health Factor × Contention Factor × 100
Estimated Goodput = PHY Rate × Throughput Efficiency %
6) Overall Score
Overall Score = Quality Composite × 0.55 + Channel Health × 0.45
This blended score produces the final grade and recommendation.
How to Use This Calculator
- Choose the WiFi band you are measuring.
- Enter the active channel number and center frequency.
- Select the current channel width in megahertz.
- Enter the measured RSSI and noise floor values.
- Fill in utilization, retry rate, and nearby network counts.
- Add the current PHY rate and site density profile.
- Click Analyze Spectrum to generate the result.
- Review the score, chart, recommendations, and export options.
Frequently Asked Questions
1) What does this analyzer estimate?
It estimates channel health using RSSI, noise, utilization, retries, and nearby network overlap. The output helps compare channels and identify congestion before changing power, channel width, or placement.
2) Is this a replacement for a hardware spectrum analyzer?
No. This page is a planning and interpretation tool. A dedicated analyzer still provides deeper visibility into non-WiFi interference, duty cycles, and real-time spectral activity.
3) Why does 2.4 GHz usually score lower?
That band has fewer clean channels and more overlap in busy buildings. It often suffers from Bluetooth devices, microwaves, and older clients, which raise airtime contention and reduce efficiency.
4) What is a good SNR target?
For reliable performance, many deployments aim for 20 dB or better. Higher values usually support better modulation rates and lower retransmissions, especially in dense environments.
5) What does channel utilization mean?
It represents the percentage of airtime already occupied. Higher utilization means less free transmission time, more waiting, and greater risk of latency and throughput drops.
6) Why does wider channel width raise overlap risk?
Wider channels consume more spectrum. That increases the chance of touching neighboring activity, especially in crowded buildings where several access points compete for the same space.
7) How should I use the result in practice?
Compare several candidate channels from the same location. Favor the option with better channel health, lower overlap risk, and stronger estimated goodput, then confirm with live testing.
8) What should I do when the score is poor?
Try a cleaner band, reduce channel width, reposition the access point, tune transmit power, or add another cell. Then rescan and compare the updated score.