Like me, some people may be constrained by the monthly cap they can consume the Internet usage. Thus, my question is,

Will replaying YouTube videos again cost you twice the network usage? I always assumed that once that I've played it, it'd be cached on my machine locally, so it won't consume any more network traffic to reply it again right afterward (without closing and re-opening the video).

However, the answer to question Can you tell by the network traffic whether a video was watched or downloaded from YouTube? seems to reveal otherwise:

  • replaying YouTube videos again will cost you twice the network usage; once more will triple the network usage
  • simply jumping back to rewind to an earlier spot might cost your network usage as well, if it falls off that internal buffer range.

Is it true, or is it still true, or I'm interpreting it incorrectly?


  • While on the subject: Trying to load YouTube in lowest quality I've been trying to find an answer for a year. Especially the part about loading in 240p. Mar 5, 2016 at 16:34
  • 2
    There are firefox extensions and probably chrome that allow you to download the video locally, and you can re-watched it 1000 times for no additional bandwidth. When you click play open a network monitor and it will either be download or not. In windows 8,8.1,and network utilization can be viewed in the task manager. You could disable your internet and hit play and see if it plays
    – cybernard
    Mar 5, 2016 at 16:40

1 Answer 1


Experience shows that "usual size" videos are cached in the browser and do not cause any further traffic for replay, so you can replay them or seek in them without generating further traffic.

As a visual hint the player shows with grey stripe where the video is already downloaded (and cached) in your browser; when the grey doesn't disappear (go back to black) it should stay cached and should not cause any traffic.

I am using the HTML5 player but this ought to stand for the flash-based player as well.

(However changing resolution require different chunks and cause them to be downloaded.)

  • This assumes you have not reloaded the page. Also, as security of the content has become a thing, and as the streamed videos are higher quality and longer in length the potential size of even a few hours of Youtube video can quickly overwhelm a computer or mobile device with normal amounts of storage. Hence many streaming protocols send chunks of the video which are then purged. So this might be true in certain limited conditions, but would not apply as generally as it may seem. Jan 5, 2017 at 23:24
  • The question specifically asked "without closing or reloading the video": you watch it then use the replay button. I don't know the specific cache sizes but I have tested for a <10 min video before answering (but my experience backs that since I often use low bandwidth connections where any traffic is easily observable). It is possibly not true for longer or large videos, but having a network cap suggest to avoid these.
    – grin
    Jan 5, 2017 at 23:31
  • @grin - You should determine those limits before you speak to them
    – Ramhound
    Jan 6, 2017 at 15:11
  • @Ramhound Apart from specifically answering the question I totally agree; unfortunately I cannot find specifics on a cursory glance and my educated guess is that this depends on the OS, the size of the browser cache, maybe the amount of RAM and possibly other factors (like flash settings). The real answer is above: when the indicator shows that the video (chunk) is already cached (grey) it will not be reloaded, when it's not then it will be reloaded, and restarting and seeking will not invalidate chunks by itself.
    – grin
    Jan 6, 2017 at 17:57

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .