FAQs
Where can I find the Xfinity Speed Test?To use the Xfinity Speed Test, go to speedtest.xfinity.com using your desktop or handheld device’s browser and select Start Test. The Xfinity Speed Test is also available in the Xfinity app (Apple App Store or Google Play) for some Xfinity Internet customers.
| Internet device type | Speed Test | Location in the Xfinity app |
| Customer-owned | Xfinity Speed Test | Available in Overview |
| Xfinity Gateway (non-xFi) | Xfinity Speed Test | Available in Overview |
| xFi Gateway (not including DPC3939 and PX5001) | Xfinity Speed Test or Device Connection Test | Available in WiFi or in WiFi > View WiFi equipment > Internet Health |
| xFi Gateway — DPC3939 and PX5001 | Xfinity Speed Test | Available in WiFi |
Who can use the Xfinity Speed Test?
The Xfinity Speed Test is available to anyone with an internet connection and a device with a web browser. The Xfinity Speed Test can be used to test a WiFi or a broadband cellular network connection.
Why should I use the Xfinity Speed Test?
If you want to find out if you're getting enough speed to support the apps you're trying to use, the Speed Test is a great tool.
For example, if you're trying to watch an HD Video on your phone, launch the Speed Test from your phone and run the test. If the HD video box is green, that means you have enough speed to stream your video.
Note: WiFi speeds vary by location (based on coverage) and by device (based on hardware capabilities). Because of this, make sure you test the device you're trying to use, in the place you're trying to use it. By running the test in different rooms in your home, you can find the best locations for streaming, or areas where your WiFi is weak.
What do my Speed Test results mean?
Here are the basics:
- 8 kilobits (Kb) = 1 kilobyte (KB); 8 megabits (Mb) = 1 megabyte (MB). KB and MB are measurements of data file sizes and storage.
- Kbps and Mbps are short for "kilobits per second" and "megabits per second" and are measurements of data transfer rates (AKA connection speed).
- To estimate how long it'll take to download a large file based on your connection speed, you can use the following simple mathematical equation:
- (Convert file size to Mb)/connection speed (in Mbps) = # of seconds to complete download.
- So, if your connection speed is 16 Mbps, then you could theoretically download a 2MB file in approximately one second. (2MB x 8Mb)/16 Mbps = 1 second.
Note: Remember the difference between megabits and megabytes. They are often confused, but mean very different things.
Why does the download test work for me, but the upload test doesn't (or vice versa)?This can happen if something that's installed on your computer is intercepting traffic between your web browser and your Internet server (e.g., security software from ZoneAlarm, McAfee or Symantec). Try temporarily turning off the software to see if it's the source of the problem, but make sure you turn it back on! Any security software should work with the Speed Test if it's set up the right way.
Why is this speed test showing faster speed results than other tests?
The Xfinity Speed Test results show the maximum connection speeds for downloading and uploading files that are between 256 Kb and 100MB in size. There are other factors that can affect your results when you run the test using a third-party site, like network traffic. Also note that actual speeds may vary and aren't guaranteed.
How do I get the fastest Speed Test results?
The Speed Test calculates the speed of your device at the specific time and location that you run the test. Your speed is affected by the type of device you have and the WiFi coverage that's available at that time (if connected to WiFi). Your results can be lower than your plan speeds because of these factors. This doesn’t mean that your Gateway isn’t getting your full plan speed, just that your device isn’t.
Learn more about how your results compare to your plan speeds.
Learn more about testing speed to Gateway.
If the Speed to Gateway Test is not available to you and you want to get an estimate of the speed that the Comcast network delivers to your home, run the test from a laptop that's connected to your Gateway using an ethernet cable. Connections that rely on WiFi may have different results that don't show the full potential of your service.
Note: If you're running the Speed Test only using an Internet connection, other programs or devices that are using that same connection may drain your bandwidth. You should turn off those devices (e.g., tablets, smartphones, network connected game consoles, etc.) and shut down all other websites and Internet apps like Netflix, Spotify, Pandora, etc. before you run the test. Also make sure you're not downloading or uploading other files at the same time.
What does my location have to do with my Speed Test result?The Xfinity Speed Test uses GeoIP data from MaxMind to determine the closest Speed Test server your location. Testing to the closet server is recommended to get the best speeds.
Why does network distance affect speed?
You've probably noticed that downloading from a local server location is faster than a distant one. That's because the TCP window is not optimized for the increased latency that comes from an increase in distance. The TCP window size determines how many packets can be sent at one time. The larger the window size, the higher the speeds. Increased latency decreases the TCP window size.
Does the location of my Wireless Gateway or router affect WiFi performance?
Yes. For optimal performance, place your Wireless Gateway or router in:
- A central location where you usually use your devices.
- An elevated location, like a higher shelf, where laptops have a line-of-sight view.
- A vertical position.
Areas to avoid:
- Areas near sources that may interfere with your connection (microwaves, high powered appliances, 2.4GHz cordless phones or other wireless devices).
- Basements, and next to other wireless routers (e.g., Xfinity Home Router).
- Areas near metal objects and surfaces.
- Areas against walls, tucked away in corners on the floor or behind furniture.
- Areas near windows.
- Areas close to halogen or fluorescent lighting.