How to Measure and Improve Your Wi-Fi Performance

Contents hide

1 1. How to find your numbers

2 2. The Calculation

3 Benchmarks for Good SNR

4 3. What does your result mean?

5 4. Key Factors Impacting SNR

6 5. The “Data Density” Jump (QAM)

7 6. Real-World Speed Example

8 7. The 6GHz “Clean Air” Advantage

9 Summary

10 Related

11 Discover more from NAS Compares

To calculate your Signal-to-Noise Ratio (SNR), you first need to find your Signal Strength (RSSI) and your Noise Level. Here is how to find those values based on the device you are using:

1. How to find your numbers

Device	How to see Signal & Noise
Mac	Hold the Option key and click the Wi-Fi icon in the top menu bar. Look for RSSI and Noise.
Windows	Open Command Prompt and type: `netsh wlan show interfaces`. Note: Windows usually only shows “Signal” as a percentage. You may need a free tool like NetSpot* or inSSIDer to see the dBm noise floor.*
Android	Use a free app like Wi-Fi Analyzer or Ubiquiti WiFiman. They will display both signal and noise in real-time.
iPhone	Download the AirPort Utility app (by Apple). Go to your iPhone Settings > AirPort Utility > turn on Wi-Fi Scanner. Open the app, tap Wi-Fi Scan, and hit Scan.

2. The Calculation

Once you have those two numbers (both will be negative), use this formula:

\text{SNR} = \text{Signal} - \text{Noise}

For example, if you have a signal strength of -41 dBm and a noise floor of -96 dBm, the SNR is 55 dB (an excellent connection). Conversely, if the noise level is high, such as -50 dBm, the same signal results in a poor SNR of 9 dB.

Benchmarks for Good SNR

What defines a “good” SNR depends on the application and the Wi-Fi standard being used:

3. What does your result mean?

SNR Result	Quality	What you can do
40 dB+	Excellent	Maximum speed; perfect for 4K streaming and gaming.
25 to 40 dB	Very Good	Very stable; everything should work perfectly.
15 to 25 dB	Low	You might notice “hiccups” or slow loading on videos.
10 to 15 dB	Poor	Frequent lag; basic websites might be slow.
Below 10 dB	Unusable	Constant disconnects; the “noise” is drowning out the signal.

4. Key Factors Impacting SNR

Distance: As a device moves further from the access point, signal strength drops while the background noise usually remains constant, lowering the SNR.
Interference: “Noisy” devices like microwaves, cordless phones, and other nearby Wi-Fi networks raise the noise floor, which reduces SNR.
Hardware Standards: Newer standards like Wi-Fi 6/6E and Wi-Fi 7 require higher SNR (typically 35–40 dB) to maintain their top speeds compared to older standards.

When we say newer Wi-Fi standards require higher SNR (Signal-to-Noise Ratio), we are referring to the Modulation (how the data is packed into the radio wave).

Think of it like writing: Wi-Fi 5 is like writing in large block letters. Wi-Fi 7 is like writing in tiny, microscopic cursive. To read the tiny cursive, you need perfect lighting (high SNR) and no smudges (low noise).

Here are the specific examples of why this happens:

5. The “Data Density” Jump (QAM)

Each new generation of Wi-Fi increases the Quadrature Amplitude Modulation (QAM). Higher QAM means more bits of data are sent in every single “pulse” of the radio signal.

Standard	Max Modulation	Required SNR for Max Speed	Analogy
Wi-Fi 5	256-QAM	~25 to 30 dB	Reading a large font book from 10 feet away.
Wi-Fi 6/6E	1024-QAM	~31 to 35 dB	Reading a standard font book from 10 feet away.
Wi-Fi 7	4096-QAM	~40 to 42 dB	Reading tiny “fine print” from 10 feet away.

6. Real-World Speed Example

Imagine you have a Wi-Fi 7 router and a new phone:

Scenario A (Near the Router): You are 5 feet away. Your SNR is 42 dB. Your phone can use 4096-QAM. You get the maximum advertised speed (e.g., 2.4 Gbps).
Scenario B (In the next room): You move 20 feet away. Your signal drops, and your SNR is now 32 dB. Even though you have a Wi-Fi 7 router, the “noise” is too high for 4096-QAM. Your phone automatically downgrades to Wi-Fi 6 speeds (1024-QAM) to keep the connection stable.
Scenario C (Behind a wall): Your SNR drops to 20 dB. Your phone now has to use 64-QAM (Wi-Fi 4 levels of density). Your speed drops significantly, perhaps to only 100–200 Mbps.

7. The 6GHz “Clean Air” Advantage

Wi-Fi 6E and Wi-Fi 7 introduced the 6GHz band.

The Benefit: In the 2.4GHz band, your “Noise” might be high (-80 dBm) because of your neighbor’s Wi-Fi and your microwave.
The Math: If your Signal is -60 dBm, your SNR is only 20 dB (Slow).
The 6GHz Switch: Because 6GHz is new and empty, your Noise might be much lower (-95 dBm). Even with the same -60 dBm signal, your SNR jumps to 35 dB.
Result: You get much faster speeds simply because the “room” is quieter, giving you the high SNR needed for advanced modulation.

Summary

To actually see the benefit of Wi-Fi 7’s top speeds, you generally need to be in the same room as the router. If your SNR is below 35 dB, a Wi-Fi 7 router will perform almost identically to a Wi-Fi 6 router.

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