Hi, is it possible to know that, if Firefox or any browser is opened, whats the amount of memory taken up by each TAB of web-browser ?

I am just curious to know.


For Firefox, I've made an addon which displays tab memory usage in the corresponding tab's title.

Provides user with tab related stats and memory usage ..




  • How many tabs are currently open
  • How many tabs have been opened during this Firefox session
  • How many tabs have been opened since addon installed
  • Display tab memory usage in title
  • Preference to toggle tab memory usage on/off
  • Preference to set interval between memory usage collection
  • 3
    This plugin is not compatible with Firefox 57 (Quantum) and up due to the new WebExtensions Framework. – Scott Stevens May 18 '18 at 14:53
  • 1
    As explained in other answers, you can use about:performance in Quantum. – NieDzejkob Jun 28 '19 at 18:59

In Firefox Quantum, you can use about:performance.

There is also about:memory where you can "view, save, load, and diff detailed measurements of Firefox's memory usage".

Answer history:


An user requested this feature five months ago in Mozilla Support forum. Quoting the answer of the moderator, "Mozilla is working on that through the Electrolysis project".


Project Electrolysis has been released! Now Firefox is also multi-process.

  • thanks but its good for firefox 4.0 and now i am at 16 . one more thing is its not showing for each TAB .what ever the functionality i can get from that add-on, i can get easily from the top or htop commands with terminal . – rɑːdʒɑ Nov 13 '12 at 4:59
  • @ican: I've found the project Electrolysis through which Mozilla will implement this feature. I also updated my answer. – Yamaneko Nov 13 '12 at 5:32
  • it seems to be not yet finished , – rɑːdʒɑ Nov 13 '12 at 14:43
  • 1
    I found that some of my add-ons disabled the multi process mode in Firefox. I solved it by following the instructions here (add the compatibility reporter add-on and it'll mark all those add-ons that are preventing multiprocess mode then disable them) - hacks.mozilla.org/2017/06/… – Chris Smith Oct 14 '17 at 1:52

Try using about:performance. It seems to give real-time data similar to Chrome's Task Manager.

The add-ons don't work in Firefox Quantum, since the add-on framework has been changed now.


Type about:memory?verbose in the url bar, and check each of window nodes. It should do the trick.

  • where i can get the description of all those text. – rɑːdʒɑ Nov 17 '12 at 2:16
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    I didn't find anything yet on Mozilla support site, but it's quite simple, just click on window type nodes and they will collpase, so you can see only parent nodes. – jasmines Nov 17 '12 at 5:59

Unfortunately the way that Firefox tabs are implemented, and the way that about:memory is structured, it is not trivial to determine the memory usage per-tab. about:memory is really a tool for debugging and development purposes, and since tabs are still part of the same process, you cannot get the same per-tab stats you do in Chrome/Chromium.

You won't get a better answer from your bounty, because there's nothing anyone can do about that at this time.

In the latest nightly from the Mozilla nightly PPA, this is what about:memory looks like (I've selected the section that shows you the open tabs):

About:memory screenshot

As you can see it is possible to tell by the URL which tab is being referred to, but in reality there is memory being used in other aspects that cannot be illustrated accurately here because it is all one process, but many threads.

  • but the chrome doing it and why can't we do something parallel . – rɑːdʒɑ Nov 22 '12 at 7:25
  • 2
    @ican: I think this is the purpose of the Electrolysis project. It will provide, in the future releases, a similar tool. – Yamaneko Nov 22 '12 at 14:08
  • @VictorHugo Hi,Thanks for the reply . :D . So i think probably i should wait up to that . :) – rɑːdʒɑ Nov 23 '12 at 2:33
  • @ican: Yeah, I hope this feature comes soon :) – Yamaneko Nov 23 '12 at 12:46

Firefox 65 released on 29-01-2019 added memory usage to the task manager page found at about:performance.


I use the other Firefox extension. It is called Tab Memory Usage, https://addons.mozilla.org/en-US/firefox/addon/tab-memory-usage/

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