When you look in List View in the Finder, you'll see a file size for every file, but no size listed for any folders. You can still view the total size of a folder using one of several methods. You can Get Info on a folder to see the size and number of files. You can also use the File Inspector. Quick Look also displays the folder size. If you want to see the sizes of all folders in List View, you can enable that by changing a setting.
Is there a preference somewhere in the Finder to enable Folder sizes to be viewed no matter which containing folder you are in? I have searched for such a preference and so far have not been able to find it, so was wondering whether it may be some hidden preference that can only be accessed via the "defaults write" command in Terminal.
Richard: You wouldn't want a setting for that. Think of how much work your Mac would constantly be doing to calculate every folder size, which would mean every file. And the system, library folders and other places sometimes have tons of small files in them. And they change, often. That's a good way to have your Mac run very slowly.
Great info as always. Curious...if there is no Finder window open, does the "calculate all sizes" option continue to take CPU time, or is it only when you open the Finder window with "calculate sizes" that the size calculation takes up CPU time?
Gary, do you see a huge difference in how long it takes to see the sizes of your external storage backup folders? I can't even use get info to see them, at least in the same day. :)
Bruce: I always assumed it would update even if not open. But I haven't tested it. Even so, if you have it on and open the folder, it would then calculate the sizes of the folders on the spot, and that means looking at every file in every subfolder, all the way down.
brad: I'd imaging that an external drive, bottlenecked through USB and also maybe a spinning disk instead of a SSD, would be slower. Plus if you are looking at some sort of backup folder it could contain so many files it would be super-slow. Think of all of the folders in folders in folders, etc, all the way down.
Gary, great post, as always. Might be useful to note that when the “Calclate all sizes” option is on, the files in list view can be sorted by size (clicking on “Size” in the header) so you can easily find folders with a large number of files.
Would the transition to the new APSF file system mean quicker folder size info?
TimA: Not sure. Been using APFS since High Sierra, of course, and I haven't noticed it being faster.