Running a bandwidth speed test provides answers to many questions about your Internet connection. Whether you’re looking to find out how quickly you can download and upload files to the Web or curious to know if you’re getting your money’s worth from your provider, an Internet speed test offers the insight you need.

Comcast Xfinity is the largest Internet service provider (ISP) in America. Boasting high-quality signals, extensive coverage across the nation, and reliable speeds and service, it’s no wonder why Xfinity is lauded as America’s best Internet experience. However, on an individual consumer basis, no two connections are the same. This means one household enjoys lightning-fast Xfinity speeds while down the street they struggles with a spotty connection.

No ISP can claim to provide flawless reliability and availability, which means that for some, broken or slow Internet is an everyday reality. The Xfinity speed test tool measures your Xfinity Internet speed by calculating the time taken for each byte to travel from the remote Xfinity server to your web-enabled device. Note that these speed test results are often lower than your plan speed due to a number of variable factors outside of your ISP’s control.

Using this guide, we’ll walk you through how to run an Xfinity speed test, help you understand your results, and answer any questions you may have about your internet speed and web connection.

What is an Internet Speed Test?

An Internet speed test measures the broadband connection parameters of your Internet. This process is completed by sending a small file from the server and analyzing the time it takes to download the file and then upload it back to the server.

Internet speed tests measure a number of important items, including:

  • Upload speed
  • Download speed
  • Bandwidth
  • Ping

Note that some Internet speed tests do not report all of these items, but speed and bandwidth are standard measurements across all tests.

How to run an Xfinity Internet Speed Test:

Step 1: Optimize your test

Before you run your Xfinity speed test, do the following to ensure your test is as accurate as possible:

  • Disable any software that can slow down the test
  • Disconnect any hardware that can cause latency issues

Step 2: Access the Comcast Speed Test

Here, you will simply be asked to “Start Test.” The test should take no longer than 30 seconds. When complete, the page will automatically refresh to your Xfinity Internet speed test results.

Step 3: Survey your results

Your speed test results will present a checklist of five items:

  • Send/receive email
  • Browse the Internet
  • Stream HD video
  • Stream 4K video
  • Speedy downloads

You will see a green checkmark next to the items your internet connection is suitable for and a red X next to those that your connection is too slow for. This will give you a better gauge of how your internet connection is (or is not) working for you.

On the same page, select “Show More” to reveal your upload speed, latency, protocol, and host. To get a more well-rounded understanding of what each of these means and measures, check out the glossary of speed test terms below.

Xfinity Internet speed test terms

What is Upload Speed?

Upload speed is the rate at which data is transferred from your device to the Internet. Upload speed effectively measures how many megabits of data per second you can send from one device to another device or server on the Internet. Common online activities, like sending emails, video-chatting, and tournament-style games, require fast upload rates. Upload speed is measured in megabits per second (Mbps).

What is Download Speed?

Similar to upload speed, download speed measures the time it takes for data to be transferred from the Internet to your device. Most bandwidth connections are designed to deliver faster download speeds than upload speeds as the vast majority of online activity (streaming videos, loading webpages, etc.) are dependent upon fast download speeds.

What is Ping?

Ping measures the reaction time of your connection, reporting how fast you’re able to get a response after you’ve sent out a request. The faster your ping, the more responsive your connection. This especially true of applications and programs where timing is crucial. Ping is measured in milliseconds (ms).

What is Mbps?

Mbps stands for “megabits per second.” This unit of measurement surveys the bandwidth capacity of an Internet connection, denoting how much data able to be transferred each second.

What is Bandwidth?

Bandwidth identifies the maximum amount of data able to be transmitted via an Internet connection within a specified amount of time. Though often mistaken for Internet speed, bandwidth actually refers to the volume of information that can be sent rather than the rate in which it is sent. Speed tests denote bandwidth in megabits per second (Mbps).

What is Latency?

Though similar to ping, latency is the measure of time between a request and a result. Latency tells you how much time it takes for a signal to travel to your ISP’s server and back. Lower latency means shorter lag time, so, the lower that number, the better. Speed tests denote latency in milliseconds (ms).

Why is my Xfinity Internet Speed so Slow?

If you’ve been struggling with a slow Xfinity connection, there are several possible explanations that could be the culprit. Take a look at these five common issues that may be holding you back from a speedy web connection.

  • Your WiFi signal is bad

A weak, spotty WiFi signal may be the reason why your Internet speed struggles to keep up with your online demands. Jarring Internet traffic slowdowns, excessive download times, and frequent disconnection are all tell-tale signs of a bad WiFi router.

Though WiFi routers are robust pieces of technology, they are subject to slow performance and breakdowns with age. While resetting the router solves many basic issues, others require a router replacement to get your connection up to speed.

  • Network latency is too high

Internet performance is largely dependent on two essential elements: bandwidth and latency. As mentioned earlier, when latency is too high, your performance quality plummets. From network throttling to congestion, there are a number of factors out of your control that can affect your Xfinity network latency.

  • You’re on a low-tier Internet plan

Like any ISP, Comcast Xfinity offers a number of service plans that work on a tier system—the faster the plan, the more expensive the bill.

If you’re unsure of what Internet speeds your Xfinity plan promises, log in to your Xfinity account and access your plan details. There you’ll be able to see what speeds you are paying for versus the speeds you actually get. In the event that your Xfinity speed test results don’t match up with what your plan offers, reach out to Xfinity Support to speak with a representative who can explain or mend your connectivity issue.

  • Your device may have a virus

If your computer contains any type of malware or virus, as a result, your web connection likely suffers. Note, these malicious bugs fester on your computer and curb your Internet speeds. Spyware, in particular, monopolizes your Internet connection and cause delays, ruining your PC performance altogether.

Running your system through an antivirus check helps you determine whether or not a digital infection is the cause of your slow web speeds.

  • Your computer is too slow

Poor PC performance oftentimes signals poor internet connection, too. If you’re dealing with a laggy rig that struggles to accommodate your everyday requests, your PC may be the problem, not your Internet connection. To check if this is the case, run an Xfinity Internet speed test on a different device. Note if the results are significantly faster than that of your PC test, assume that your computer is the problem.

Freeing up hard drive space, clearing your cache, deleting files, and emptying your digital trash can are all easy ways to speed up your computer and make more room for speedy connectivity.

What Factors alter Xfinity Speed Test Results?

In order to reap accurate speed test results, you must first ensure your environment is ideal for the test. There are a number of factors that can warp your speed test results and obscure your true results. These factors are either software or hardware discrepancies. Let’s break it down:


Certain types of software programs installed on your computer can cause major connectivity slowdowns. If you’re running too many apps that require a web-connection to function, performance will likely take a hit. Some software programs also run in the background without you knowing, slowing you down all the while. Not only can software affect your real-time connection quality, but it can also affect your Xfinity speed check results.

Firewalls, antivirus programs, and administration tools are common PC software programs that can slow down your speeds and alter your speed test. These programs effectively monitor each and every piece of data sent to the computer. In some cases, they supply extra data to help with encryption. Before running an Xfinity speed test, be sure to disable all of these programs.

Your browser of choice (Chrome, Safari, Edge, Firefox, etc.) may also yield different results.  Each browser varies in its performance capacity, which is why you may see different results from an Xfinity speed test conducted in Chrome versus Safari. Though there is no definitive answer to which browser is best, it’s wise to run your speed test on your most preferred browser to get an accurate glimpse at your regular speeds.


All types of web-connected devices produce different speed test results even when using the same exact ISP. Expect different results on a tablet or smartphone compared to a desktop computer. These are due to available bandwidth, internal hardware, and connection type.

Your Internet speed heavily depends on the availability and quality of certain network equipment. In most cases, the router or modem hold responsibility for connecting you to the Web.

When dependent upon a wireless router connection via WiFi, expect slower speed test results than a wired Ethernet connection. Ultimately, stability plays a significant role in determining your Internet’s performance.

The number of users on a single household connection can also affect your Internet speeds. This is also true of your larger ISP network connection. If you happen to conduct an Xfinity Internet speed test during work hours while most people are active online, the results are likely going to be less impressive than the results you’d get during a test beyond peak hours.

What is considered Fast Internet speed?

The FCC stated that fast Internet is a connection offering download speeds of at least 25 Mbps and upload speeds of at least 3 Mbps. These speeds seamlessly support most common online activities, including HD video streaming, online gaming, and music downloading.

Download speeds of at least 25 Mbps easily accommodates the average household’s needs. However, a larger household or the need for extra bandwidth for more intense online demands might require a faster tier.

What is considered Slow Internet speed?

Based on FCC evaluations, download speeds below 25 Mbps are too slow to be considered broadband.  Expect frequent video-buffering, difficulty connecting multiple web-enabled devices, and a slew of other frustrating connectivity issues.

It’s important to note that DSL is the most common type of Internet that offers speeds below the standard 25 Mbps. DSL may not be as popular as it used to be. However, it still provides a sound solution for those looking for a reliable connection for basic online activities. These include streaming, online gaming, casual browsing, and more. Ultimately, if your speed is under 25 Mbps but is fast enough for you, there’s no cause for concern.

How can I make my Xfinity Internet faster?

Before contacting Xfinity Support, check if you’re currently downloading something. Or a bandwidth-hogging program might be slowing down your connection. Our suggested hardware and software modification tips let you run multiple speed tests as possible. This approach achieves the most accurate results.

If your Xfinity speed test results still seem too slow for your liking, try rebooting your device, modem, and router. Often this can repair any slowdown problems you may have encountered.

If all else fails, contact Xfinity Support for help. A service representative may be able to help you solve your connectivity issues. Ultimately, consider a higher tier plan for your online demands?

Paul Williams
Paul Williams

Paul Williams brings a wide range of experiences to his writing. He worked extensively in technology, as a software engineer, technical writer, and now a technology writer. Known as the leader of one of the top American Spacerock bands, his forward-looking music continues to be heard all over the world.