How To View Folder Sizes

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.

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Video Transcript: One of the things that frustrates Mac users from time to time is the difficulty in being able to see the size of a folder. You can see the size of a file but a folder just doesn't show any size. Let me show you an example here.
Here's a bunch of folders and some files. If I switch to List View you can see I can see the Name, Date Modified, and I can see Size. Notice that the three files here show a size but I just get two dashes for all the folders. So how do I know the difference between a folder that has a couple of K of files and one that's like a hundred mg? You don't know. Well, there's several different ways to find out the size of all the files in the folder total.
One thing you can do is you can select the folder and get info on it. So you do that by going to File, and then Get Info or Command I as the shortcut. The info window will show you the total size of all the files in the folder and also the number of items. So you can do that for individual items.
Now if you do Option, Command I, and you can see here if I hold the Option key down it says Show Inspector, so Option, Command I brings up the Inspector. Inspector looks just like the info window but you can select different things and it will change whereas the Info window always remains the info for the thing that you brought it up for originally. So now I can go through these. I can even use the down arrow here to go through and see the size of all these folders appearing here.
Now another way to do it is to simply hit the Spacebar for Quicklook. When you do that for a folder you should get the size here. I can use the spacebar for any of these folders so I'll do it here. I can use the arrow keys to go up and down between them. So I can see here in Quicklook the size of the folder. 
Now if you want to actually see them here, you want these dashes replaced, you can do that too. Go to View, and Show View Options or Command J. Then here there is an option for Calculate All Sizes. I turn that On and you can see now I have size information here. You may ask why is that not on by default? Why not have it there? 
Well, the idea is that it takes time to calculate these things. Sure these folders here in my Documents folder have, maybe, a few or a dozen files in them and it does it pretty much instantly. You can see how instantly it appears. But imagine if you're working with projects that have thousands of files in folders and you've got hundreds of these types of folders. The System file is one of that's like that. The System Folder. So calculating the size actually takes a lot of time. So in order to speed things up and make the Finder really zippy this is off by default. But you can certainly turn it on and it will remember that it's on for this folder here. So in this case, in my Documents folder, I might just want to leave it on if I always want to see those there. If it's something I'm constantly looking for.

Comments: 9 Responses to “How To View Folder Sizes”

Richard Fuhr

6 years ago

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.

Gary Rosenzweig

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.

Bruce Mann

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?

brad

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.

Rick Torchia

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.

TimA

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.

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How To View Folder Sizes

Comments: 9 Responses to “How To View Folder Sizes”

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