Network Management Information Center


Your Internet Service Performance

Comcast provides residential and commercial customers with a variety of high-speed Internet plans from which to choose, ranging from our Economy tier (with download speeds up to 1.5 megabits per second ("Mbps"), and upload speeds up to 384 kilobits per second ("kbps") to our Extreme 105 tier (with download speeds up to 105 Mbps, and upload speeds to 10 Mbps). Comcast provisions its customers' modems and engineers its network to enable its customers can enjoy the speeds to which they subscribe. However, Comcast does not guarantee that a customer will actually achieve those speeds at all times. Unless a customer purchases an expensive, dedicated Internet connection, no Internet Service Provider ("ISP") can guarantee a particular speed at all times. Comcast advertises its speeds as "up to" a specific level based on the tier of service to which a customer subscribes.

The "actual" speed that a customer will experience while using the service depends upon a variety of conditions, many of which are beyond the control of an ISP such as Comcast. These conditions include:

  1. Performance of a customer's computer, including its age, processing capability, operating system, the number of applications running simultaneously, and the presence of any adware and viruses.
  2. Type of connection between a customer's computer and modem. For example, in-home wireless connections between the computer and the router or modem may be slower than wired connections. In-home wireless connections also may be subject to greater performance fluctuations, caused by factors like interference and congestion. Comcast recommends that customers confirm that their in-home wireless connections are able to support the speeds that Comcast's services deliver. Certain older in-home wireless connections and routers cannot perform at the speeds delivered by Comcast's higher speed tiers. Customers can purchase their modem and router at a retail outlet, or they can lease the necessary equipment from Comcast, though even wireless routers leased from Comcast are subject to the same limitations mentioned above.
  3. The distance packets travel (round trip time of packets) between a customer's computer and their final destination on the Internet, including the number and quality of the networks of various operators in the transmission path. The Internet is a "network of networks." A customer's Internet traffic may traverse the networks of multiple providers before reaching its destination, and the limitations of those networks will most likely affect the overall speed of that Internet connection.
  4. Congestion or high usage levels at the website or destination. When you access a site or particular destination that is being visited by others at the same time, you may experience a slower connection if the site or destination does not have sufficient capacity to serve all of the visitors efficiently at the same time.
  5. Gating of speeds or access by the website or destination. To control traffic or performance, many websites limit the speeds at which a visitor can download from their site. Those limitations will carry through to a customer's connection.
  6. The performance of the cable modem you have installed. Modem performance may degrade over time, and certain modems are not capable of handling higher speeds. Please visit MyDeviceInfo for information regarding cable modems approved for use on Comcast's network.


Recently, the Federal Communications Commission ("FCC") concluded a nationwide network performance test of the largest ISPs in the U.S., including Comcast. The results of that test can be found at According to that test, Comcast's Xfinity Internet services were shown to deliver, on average, over 100 percent of their advertised downstream and/or upstream speeds during the busiest periods of the day, during sustained testing. Below are the Comcast results by tier:

Comcast Tier Name Speed
Down (Mpbs) Up (Mbps)
Tier Measured Tier Measured
Economy 1.5 1.46 0.384 0.42
Performance 12 12.44 2 2.24
Blast! 16 15.26 2 2.24
Blast! 20 20.41 4 4.61
Ultra 22 23.23 5 5.48

Again, while individual experiences may vary, the FCC's test validates the superior quality of Comcast's Xfinity Internet services.

Additionally, the FCC's speed tests did not include Comcast's new Performance Starter Tier or either of Comcast's Extreme Tiers - Extreme 50 or Extreme 105. Data gathered from our own speed tests show that the average speed customers experience should fall at or near the advertised downstream and upstream speeds. The results of our testing are as follows:

Comcast Tier Name Speed
Down (Mpbs) Up (Mbps)
Tier Measured Tier Measured
Performance Starter 6 6.34 1 1.03
Extreme 50 50 52.21 10 9.97
Extreme 105 105 102.14 10 10.41

But you also can test your speeds yourself. Comcast offers its customers the ability to test the speeds that they are receiving on Comcast's network - from the customer's computer to test sites located throughout Comcast's network. Simply go to to test your connection. These tests are heavily dependent on many of the factors outlined above, however, and therefore do not necessarily reflect the performance of the Comcast network.

There are other speed tests that measure Internet performance. We have provided links to a few of these sites below for your reference. Please note, however, that all speed tests have biases and flaws. Each of these tests measures limited aspects of an ISP's speed and therefore must be seen as a guide rather than definitive measurements of performance.




In addition to offering consistent Internet speeds, as confirmed through the FCC's Broadband Measurement Report, Comcast provides customers with the PowerBoost® feature on Comcast's Performance through Blast! tiers. PowerBoost® is a technology developed by Comcast, and used by other cable companies, that permits customers to use excess capacity in the network to speed up larger file downloads and uploads for a short period of time. Once the PowerBoost® interval expires (as determined by the size of the file being downloaded or uploaded), the customer's speed returns to the original provisioned speed. PowerBoost® will then be available again to that customer shortly after its previous use. As a result, in many circumstances, Comcast customers experience speeds in excess of that provisioned as part of their chosen speed tier. The recently-completed FCC test measured the effectiveness of our patented PowerBoost® technology and found that, on average, PowerBoost® delivers over 150 percent of provisioned speed in the downstream direction and over 200 percent of provisioned speed upstream.


Latency is another measurement of Internet performance. Latency is the time delay in transmitting or receiving packets on a network. Latency is primarily a function of the distance between two points of transmission, but also can be affected by the number and quality of the network or networks used in transmission. Latency is typically measured in milliseconds, and generally has no significant impact on typical everyday Internet usage. As latency varies based on any number of factors, most importantly the distance between a customer's computer and the ultimate Internet destination, it is not possible to provide customers with a single figure that will define latency as part of a user experience.

As discussed above, the FCC recently concluded a nationwide network performance test of the largest ISPs in the U.S., including Comcast. Latency tests were performed using User Datagram Protocol ("UDP") packet tests that measure the round trip time it took those packets to travel between a customer location and a target test node. According to the FCC's test results, the cable industry average latency was approximately 28 milliseconds, and DSL averaged 44 milliseconds. Below are the Comcast results by tier:

Comcast Tier Name Latency
Economy 24.4 ms
Performance (12/2) 25.2 ms
Blast! (16/2) 26.9 ms
Blast! (20/4) 23.8 ms
Ultra 23.8 ms

Again, these figures do not include Comcast's new Performance Starter Tier or its Extreme 50 and Extreme 105 Tiers because they were not included in the FCC's testing. Data gathered from our own latency tests are as follows:

Comcast Tier Name Latency
Performance Starter 26.9 ms
Extreme 50 20.1 ms
Extreme 105 19.7 ms

The results do not define latency as part of a particular user experience because (i) the results include time spent traversing networks not controlled by Comcast; and (2) the geographic distance between any given user and the target node may vary greatly from those employed in the FCC's broadband measurement project. But customers can test the latency characteristics of their service at Of course, this test also may incorporate limitations in a customer's home network and computers, and therefore will not necessarily reflect the performance of the Comcast network.

There are other latency tests available on the Internet. We have provided links to a few of these sites, above in the Speed Test Section, for your reference. As previously explained, however, all tests have biases and flaws, and therefore must be seen as a guide rather than definitive measurements of performance.

Xfinity WiFi

In addition to the residential or commercial Internet service that you to enjoy at your home or office, Comcast provides its Internet subscribers with XFINITY WiFi, which allows Internet subscribers to access, at no additional cost, the Internet through up to three devices when you are in one of our many, public WiFi hotspots. Comcast engineers the underlying network to deliver high-performance access to the Internet. Specifically, Comcast provisions to each hotspot a connection that provides a maximum of 5 Mbps. However, the performance you experience, once you connect to the hotspot, may vary based on any number of factors, such as the number of other subscribers trying to use the same hotspot at the same time, your computer or wireless device, your WiFi receiving antenna, your distance from the hotspot router, and interference from other devices using the same spectrum, in addition to many of the factors already mentioned above. Comcast does not manage these WiFi hotspots, and thus this service is accessed on a "best efforts" basis. These WiFi hotspots use spectrum that the FCC has allocated for "unlicensed" use, which means that, like wireless routers used for in-home networking, our use of this spectrum is not protected from interference from other devices using the same spectrum in the same geographical area. This makes it inherently difficult to predict what kind of performance you can expect.

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