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How to Measure Your Wi-Fi Signal Strength with NetSpot

Wi-Fi signal strength is an important factor in metering reliability and speed of your wireless connection. Poor wireless network signal strength can result in a frustratingly slow and unreliable Internet connection.
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Of course, signal strength is only half the equation. The level of noise in relation to your WLAN signal strength (the signal-to-noise ratio) is also very important. Give NetSpot a try, it's a professional WiFi signal strength meter, and it's free.

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Measure Your Wi-Fi Signal Strength on Mac OS X and Windows

When setting up and maintaining a wireless network, you'll want to maintain good signal strength in all areas within the network perimeter. "Dead" spots of weak signal strength can cause connections to be dropped. With more and more people moving around while connected to the Internet through their smartphone or tablet, these dead spots have become more problematic.

Increase WiFi Signal Strength
Increase WiFi Signal Strength

How to Measure Your Wireless Network Signal

You don’t have to be a computer expert or professional network administrator to measure WiFi signal strength. In fact, all you need to do is choose one of the WiFi signal strength measuring methods described below and follow our step-by-step instructions.

Method 1:
WiFi analyzer app runs on a MacBook (macOS 10.10+) or any laptop (Windows 7/8/10) with a standard 802.11a/b/g/n/ac wireless network adapter.
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NetSpot is a wireless signal assessment and site survey application for Mac. It provides two ways of measuring your WLAN signal strength.

  • Discover mode

    Reflects the rate of data transfer from user to the Internet.
  • Survey mode

    Available on any MacBook with macOS and PC laptop on Windows.

The first — and quickest — way is to use Discover Mode:

  1. Open NetSpot.
  2. Change the slider located in the upper-left corner to the Discover position.
NetSpot Discover Mode
  1. NetSpot will automatically find all wireless networks in your area and provide you with detailed information about them, including signal strength.

If you just need to measure your wireless network signal strength in one location, then Discover Mode is all you need. However, if you wish to measure signal strength throughout your network area, you'll want to do a full site survey. This is how to do it:

  1. Open NetSpot.
  2. Change the slider located in the upper-left corner to the Survey position.

NetSpot Survey Mode
  1. Start a new survey.
  2. You will be asked to either draw a map of your area using NetSpot's map drawing tool or upload an existing one.

NetSpot’s map drawing tool
  1. With the map ready, you can methodically move through the entire surveyed area until you’ve covered it all.
  2. When done, click the Stop Scan button in the bottom-left corner.

Method 2:
Use a Built-in WiFi Signal Strength Utility

Apple’s macOS and Microsoft’s Windows come with built-in support for wireless network connections and corresponding utilities that allow users to connect to WiFi networks and measure WiFi signal strength. These utilities are arguably the quickest and easiest way how to measure the strength of a wireless network, but their accuracy tends to be subpar, which is why we can’t recommend them over NetSpot.

This is how to use the built-in WiFi signal strength utility on macOS:

  1. Press Command + Shift + G to bring up the Go To Folder window.

Step 1
  1. Enter: /System/Library/CoreServices/Applications.

Step 2
  1. Enter password if asked.
  2. Double click on Wireless Diagnostics.

Step 4
  1. A window will appear, asking you to run a diagnostic test to determine the current state of your WiFi.

Step 5
  1. From the Wireless Diagnostics' menu bar, select Window > Monitor.

Step 6

You can also try other Window options, like Scan or Performance, to see other useful diagnostic information.

This is how to measure WiFi signal strength on Windows:

  1. Open the Control Panel.

Windows Control Panel
  1. Select Network and Internet and go to Network Connections.

Windows Network Connections
  1. Right-click the wireless connection you want to measure and choose Connect / Disconnect to see the WiFi strength.

Of course, you can always simply click on the WiFi indicator icon located in the taskbar on Windows and macOS and count the number of solid bars.

Method 3:
Use an Online Internet Speed Test

An online internet speed test won’t actually be able to measure your WiFi signal strength, but they can tell you the maximum download and upload speeds your internet connection can achieve. By comparing the measured speeds with the speeds declared by your internet service provider, you can get a pretty good idea about the strength of the WiFi signal in your location.

Just keep in mind that there are many other factors that can potentially influence your download and upload speeds, such as the software you run, number of users on your network, ISP network bottlenecks, and more.

To measure your download and upload speeds using an online speed test:

  1. Go to: https://www.speedtest.net/
  2. Click the Go button and wait for the test to finish.

Speedtest by Ookla
  1. Compare the results with the download and upload speeds advertised by your internet service provider.

Speedtest by Ookla is just one of many internet speed test applications that are readily available online. Popular alternatives to Speedtest by Ookla include Fast.com, SpeedOf.Me, TestMy.net, Internet Health Test, and SpeedSmart. The main reason why Speedtest by Ookla has earned our recommendation has to do with the fact that it has servers all around the world, which ensures high accuracy of its tests.

Understanding WiFi Signal Strength

The common name for the received radio signal power level in a wireless network is RSSI (Received Signal Strength Indicator). WiFi signal strength is typically measured in decibel milliwatts (dBm), a unit of the level that is used to indicate that a power ratio is expressed in decibels (dB) with reference to one milliwatt (mW).

When interpreting this unit, it’s important to keep in mind that the decibel scale is logarithmic and not linear. As such, 3 dB increase in level doubles signal strength, while 10 dB increase in level is equivalent to a 10-fold increase in power. To better understand what this means in practice, let’s take a look at the table below, which describes various levels of signal strength loss and how they affect network performance.

Strength -30 dBm
Summary Amazing
Expected quality Minimum signal strength for applications that require very reliable, timely delivery of data packets.
Required for N/A
Strength -67 dBm
Summary Great
Expected quality The maximum signal strength that is achievable under controlled conditions.
Required for Voice over IP and real-time streaming video
Strength -70 dBm
Summary Average
Expected quality Minimum signal strength for reliable packet delivery and tasks such as email.
Required for Email and light web browsing
Strength -80 dBm
Summary Poor
Expected quality Minimum signal strength for basic connectivity, such as connecting to the network.
Required for Connecting to the network
Strength -90 dBm
Summary Unusable
Expected quality Extremely poor signal strength that makes any functionality, including connecting to the network, highly unlikely.
Required for N/A

Generally, signal strength between -55 dBm and -75 dBm is acceptable, depending on how close or far away from your wireless router you happen to be. If you’re in the same room as your wireless router and have trouble achieving good network performance, the chances are that there is a lot of environmental noise from various electronic devices and other wireless networks.

You can see just how much noise there is by measuring the Signal-to-Noise ratio (SNR), which is the difference in decibels between the received signal and the background noise level. For example, if you receive a signal of -70 dBm and the noise floor is measured at – 80 dBm, the SNR is 10 dB. Of course, you want the Signal-to-Noise ratio to be as high as possible so that it’s less likely for a signal to disappear in environmental noise.

Troubleshooting Your WLAN Signal Strength

Once you have completed your survey, there are three WiFi heatmap visualizations you will want to view:

  1. The first is Signal Level. This will show you the WLAN signal level throughout the area you surveyed. Blue and purple areas are places where the wireless network signal is weakest.

Signal level
  1. Then you'll want to view the Signal-to-Noise Ratio heatmap. A lot of environmental noise (from microwaves, cordless phones, fluorescent lights, etc.) can make even a decently strong signal virtually unusable.

NetSpot Signal-to-Noise Ratio heatmap
  1. Third, view your Signal-to-Interference Ratio — this measures the channel interference from other wireless networks. Again, the blue and purple areas are the ones of greatest concern.

NetSpot Signal-to-Interference Ratio

Once you've identified areas of low Wi-Fi signal strength, you can take steps to correct it. Options include: moving an access point/router, adding a new access point, or installing Wi-Fi signal repeater or a WiFi extender.

If it's a high noise level that's the problem, you can take steps to reduce the noise by moving your access point, moving or shielding the interfering device, or switching from the 2.4 GHz band to the 5 GHz one. If the problem is high levels of interference, try changing channels to one with less interference. See these troubleshooting guides to learn more about signal level, noise level and channel interference.

WiFi analyzer app runs on a MacBook (macOS 10.10+) or any laptop (Windows 7/8/10) with a standard 802.11a/b/g/n/ac wireless network adapter.
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Wi-Fi Site Surveys, Analysis, Troubleshooting runs on a MacBook (macOS 10.10+) or any laptop (Windows 7/8/10) with a standard 802.11a/b/g/n/ac wireless network adapter.