Technology Explained

Understanding Your Internet Speed

Guy McDowell 07-10-2009

Have you ever done a speed test on your Internet connection? A lot of people have, and they see Internet speed numbers like 500 Kbps or 2 Mbps or sometimes even higher numbers. Then they turn around try to watch a streaming video on YouTube and the video stutters or stops for seconds at a time.


understanding internet speeds

More often than not, an average computer use will blame the Internet connection speed with a question, such as “Why does the speed test tell me I can download this 3 Mb video in 2 secs, yet it keeps stopping?” Or, “My speed test tells me my upload and download speeds are 512kBps. Why won’t my Skype work better?”

Hopefully, I’ll be able to shed some light on this issue for you and help with understanding Internet speeds.  Your Internet speed test only tells you part of the picture. What a speed test measures is how long a certain amount of data takes to travel to the test server and back to your computer. Based on the size of the file and the time from which it leaves their server to get to your computer, the test calculates your download speed. The size of the file and the time it takes to leave your computer and get to their server determines your upload speed.

Usually your download speed is greater than your upload speed. Why is that? Well, with average web usage, you typically send a few letters here, a click there. That’s your upload overhead. The website or video that you watch as a result of those clicks and letters is the download over head.

It’s like you sending a Smart Car to request that they send you a fleet of tractor trailers. You only need one lane for the Smart Car, but you might need 14 lanes for the tractor trailers. This is known as asynchronous communications. This is why your upload speed is usually less than your download speed.


understanding internet speeds

So, what does that have to do with your 3mbps connection resulting in jittery video? Exactly that, those speed tests don’t measure jitter! Yes, jitter is a real technical term. Imagine a train coming into the station. Each car on that train arrives at the station at the same intervals, because each car is the same distance apart. However, if each car came in with different distances between the cars, well, you can imagine what a mess that would make!

It’s the same thing for packets of information on the Internet.  The fluctuation of the time between those packets, even if ALL the packets are traveling at 3 Mbps causes jitter.  Significantly high jitter levels can cause your VoIP to not work. When we talk our voice is a continuous stream of information, so the data needs to be continuous too!  Same with video!

internet speeds explained


Another cause of Internet speed not being what it seems, is the number of hops a communication needs to make to get to the final server. Let’s say you test your speed against server XYZ. Let’s also say that there are no hops between your computer and server XYZ. Then you are told your download speed is 3 Mbps. Awesome!

Now you try to download something from server DFG. Yet, there are 14 hops, or servers, that your communications have to go to, to hit server DFG. Well, whichever one of those hops is the slowest to respond sets the maximum speed of your communication. We like to call that a bottleneck. You can have a Ferrari, but if you’re on a dirt road, you can still only go so fast. You never get to go the full speed you are capable of.

internet speeds explained

There are many different points for bottlenecks to show up, between the server you’re connecting to, and seeing the final event on your monitor. Your Internet router may be capable of less speed than your Internet connection. That’s a bottleneck. Your Network Interface Card may be capable of less speed than your router. That’s a bottleneck. Your video card may only be capable of processing the information at a lower speed than your NIC card can deliver it to your computer. There’s another bottleneck.


understanding internet speeds

One more point to consider is that your bandwidth may be getting divided amongst a number of computers in your home. If my Internet modem is capable of 3 Mbps but I have four computers downloading things at the same time through the same modem via a router, that 3 Mbps resources is now shared amongst those computers. At any point in time, any one of those four computers is going to have an Internet access speed less than that of the modem.

internet speeds explained

Well, what can we do about this then? That depends. What do you want to do about it?  What can you deal with? Me, I’m patient enough to download the whole video to my computer and watch it that way. You might not like that. Maybe you’ll want to upgrade those computer components that are causing bottlenecks. A new video card with greater processing power. A better wireless router — maybe something in the N class. A different Internet service provider or a higher speed package might be in order.


My opinion is to kick back and relax and enjoy the fact that we have this amazing technology. Only five minutes to download a song instead of driving to the record store and waiting in line for the latest Rush album. But then again, that’s just me!

Related topics: Bandwidth, Computer Networks.

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  1. Lindsay
    November 20, 2019 at 6:59 pm

    Great information. thanks!

  2. Lindsay
    November 20, 2019 at 6:23 pm

    Great information for learning. Thank you.

  3. nisha
    November 18, 2017 at 5:57 pm

    very good information & useful job thanks.

  4. nisha
    November 18, 2017 at 5:55 pm

    very good information & good work for learning. thanks

  5. Daniel Cruz
    October 13, 2017 at 1:27 am

    is very good information and neccesary for new learning

  6. Miguel
    July 27, 2017 at 1:10 am

    Thanks for the info. Much appreciated.
    I have a question. I have wifi internet 200/200Mbps from Optimum (using Optimum's modem and router). When I run a speed test on my Android cell phone using the Avast Mobile Security app, it shows download 7,59Mbps / upload 4,36Mbps. What does that mean? It means fast? How fast?
    I really hope you can help. Not sure if I should switch to Fios.
    Many thanks again.

  7. nader
    July 4, 2017 at 11:11 am

    Than you

  8. RM
    February 24, 2017 at 10:38 pm

    Thank you, your info was very enlightening as well as the comments that followed.

  9. Jason Frank
    January 9, 2017 at 3:38 pm

    This was very helpful. Thank you!

  10. John A
    September 14, 2016 at 9:26 pm

    This is certainly compelling, and it might explain something which has confused me for years. In my area Comcast boasts services up to 75 mbps. AT&T is the only competitor, and their fastest internet package tops out at 18 mbps. I've had them both back and forth repeatedly since the two companies compete for my business, and I noticed that AT&T's service seemed a match if not faster and more reliable than Comcast's. So I experimented a bit.

    Multiple third-party speed tests, run on near identical computers side by side, connected to hardlines, with one connecting through Comcast and the other through AT&T, showed that the speeds were consistently in the ballpark of what was advertised. But according to a simple stopwatch, the web browser using AT&T's connection loaded site after site faster and more smoothly.

    So, here's my current situation. Recently purchased gaming PC, runs like greased lightning when I visit my mother-in-law and connect to EPB for 1 gbps service (but it's still not worth visiting). Routers are also new, designed to handle fiber optic speeds. So it's probably not my hardware.

    That leaves me with three questions.

    1. Do ISPs have anything to do with what servers you connect to the internet through?
    2. Is jitter dictated or influenced by ISPs, whether deliberately or inadvertently?
    3. If yes to either or both of these questions, is it conceivable that they would have sufficient influence on a web browser or other internet application as to make a 75mbps connection and 18 mbps nearly identical from the user's perspective?

    • Rye
      November 12, 2016 at 6:15 pm

      I know this might be a little late but the answer your looking for is latency. That is simply the ping time which is the round trip time from your network to a server and back to present you with the information you were looking for. Latency is the "real" speed of your connection. Of course all of this is just a point of perspective but that is the exact reason why your AT&T pages load faster. They probably have a lower latency which means it can grab information from a server faster. The only time the actual speed comes into play is when that 18mbps is being maxed out by multiple devices which causes your latency to rise.

  11. jose
    September 14, 2016 at 7:24 pm


  12. grotemuis
    September 7, 2016 at 2:47 pm

    Thank you! This finally makes sense, for the most part, since I am totally not tech smart.
    I receive 768k download and 348k upload (that's what my provider sells me)
    When I do the speed test it shows 5.00Mbps download and 3.92 Mbps upload, one other test showed 1.67Mbps download and 3.50Mbps upload.
    How does that translate to 768k etc? What does k and Mbps even mean?
    I cannot watch video clips as they constantly buffer.

  13. alloe mukherjee
    July 28, 2016 at 3:40 pm

    very informative

  14. Ronald
    June 7, 2016 at 8:19 am

    how do we / what's the best way to explain to our boss re source speed? He is downloading some from microsoft and he is getting less than 100kb and complains. I test speed using speedtest via a server in another country and it reports that we have 10mbps up and down; I download a youtube file or an installer from another source and I am getting 1.1 megabytes per sec.

    • Guy McDowell
      June 15, 2016 at 1:35 pm

      I'd want to check and make sure the slowdown wasn't in your network, or on his computer.

      Also, how is he downloading it? Through a web browser, download manager, via torrent? Those may have speed limits set on them and you may be able to change them.

      If it is Microsoft or your ISP keeping it slow, one way to explain it is to use an analogy. You can put a firehose on a kitchen tap, but you're still only going to get kitchen tap water flow.

      • Josh Sese
        July 2, 2016 at 2:59 am

        Try using Go to Settings and set the Speed Measurement to kilobytes. You'll discover why you're only getting that download speed. ;)

  15. Hamza
    May 1, 2016 at 12:54 pm

    yes, that's great . thank you very much for all this information.

    • Guy McDowell
      May 20, 2016 at 7:51 pm

      Glad I could help! :D

  16. Anonymous
    September 4, 2015 at 7:55 am

    i have a question, so for example, one of my family member watching youtube it cost 1mbps and my internet speed is 8mbps, it should be 8mpbs-1mbps left 7mpbs, and yet why i am still suffering slow internet speed.

    and sometime i am home alone, there is my pc and phone is connecting. while playing game its lag too, but after i disconnect my phone wifi and everything goes smooth. can i have an answer =D

    • George Deering
      March 3, 2016 at 11:08 pm

      It depends on the device watching the YouTube video, and the device that is trying to use the left-over bandwidth. Computers and laptops usually have a powerful Network Interface Card (NIC) which is basically the part of your computer that connects to your Wi-Fi network.
      The most bandwidth will go to the device that has the most powerful NIC. So, for example, if two people are both watching YouTube videos, there will be less "jitter" on the device with the most powerful NIC, if the two devices are exactly the same then the most bandwidth will be sent to the closest device to your router or AP.
      Also, if only one person is trying to access the internet, they will use the full bandwidth available. If another person then connects, the bandwidth is split. So the first device (watching a YouTube video) will use the most amount of bandwidth it can possibly access.
      So, in short, the device in your home watching the YouTube video probably has a more powerful NIC than the second device trying to access the internet, the first device could also be closer to your router.

  17. Anonymous
    July 6, 2015 at 4:25 pm

    What are the chances that I am listening to Rush as I am reading this article! Thanks for the information written, it has helped a lot! :)

    • Guy McDowell
      July 10, 2015 at 7:08 pm

      Glad I could help. Rock on!

  18. Attia
    April 26, 2015 at 7:42 am

    If im going to download game and it's 2G and my internet speed is 512 kb/s how to measured the time is required to download it ?

  19. Bob
    April 9, 2015 at 8:27 pm

    Very nice article, finally some understandable language about the internet. Could you eplain a little more about what overhead is? I'm especially aiming for 'upload overhead', considering I upload fe an attachement with 10 kb/s (upload speed) and the upload overhead sais 100 kb/s. Does this mean I use 10 or 100 kbs of my 1mbs upload connection?

  20. Maira Pari
    February 25, 2015 at 4:34 pm

    very informative article .. keep it up.. and is explained in a friendly manner.

    • Guy
      February 25, 2015 at 5:50 pm

      Thank you Maira. :)

    January 7, 2015 at 2:17 pm

    everyonez doubts will be cleared after reading the article.

  22. Philip
    October 10, 2009 at 7:38 am

    There is a substantial difference between "asynchronous" and "asymmetrical". I suspect you mean the latter since your description entails differing upload and download speeds. Synchronous communication is goverened by a clock of sorts (think motherboard => system clock => internal bus speed) and asynchronous can happen, although at a set speed, at any random time.

    • Guy McDowell
      October 10, 2009 at 7:11 pm

      You are correct! Thank you!

  23. Marc
    October 8, 2009 at 11:39 am

    A place to test Jitter and Packet Loss along with up/down speeds is: VOIP Speed Test.

  24. roger
    October 8, 2009 at 10:21 am

    explains why my 7.4 !*&!ing Mbps (thankyou doesn't match reality

  25. Angel
    October 8, 2009 at 7:00 am

    I would like you to comment on something I noticed (or I seem to have noticed) when downloading videos from P2P sources. Apparently, if you download just one video or movie at a time, the operation is rather slow. But if you do the same with five or ten or even more more videos simultaneously, then the download seems to proceed much faster, perhaps, in my humble opinion, due to a more efficient use of the bandwidth. Am I right?

    • Tom
      October 8, 2009 at 7:23 am

      P2P software balances you uploads and downloads. Angel, I suspect in your case that you do not have many popular uploads available for other people to download. Therefore when you are downloading lots of things then as the data lands on your hard drive is immediatly available for upload, so you have more to share and your download allocation will increase. When you complete these downloads and remove them from you P2P sharing folder then you upload speed will reduce in turn

  26. watermelongirl
    October 8, 2009 at 6:26 am

    finally! a simple guide to internet speeds!
    thank u, the packets and jitter thing made everything easier to understand.

  27. Versatile
    October 7, 2009 at 2:35 pm

    A video card has nothing to deal with downloading and watching things on the Internet, does it?

    I'm sure a basic integrated graphics card is more than enough these days to watch youtube.

    • Guy McDowell
      October 7, 2009 at 6:22 pm

      A video card with little to no on board memory can be a bottleneck between the video being downloaded and it playing on your screen without pauses.

  28. Joe
    October 7, 2009 at 2:03 pm

    Very informative article!

  29. amazo
    October 7, 2009 at 1:04 pm

    usually, people just don't know the difference a Byte and a bit.

    • Mike
      February 24, 2017 at 1:52 pm

      Thanks Guy. The explanation on Internet speed was very helpful!