Disk & Storage Guide
By Windows Explorer does not show folder sizes in the Size column, and there is no setting that makes it. To see a folder's size, hover over it for the folder tip or right-click and open Properties. Or run (Get-ChildItem -Recurse -File | Measure-Object Length -Sum).Sum in PowerShell from inside the folder. If the tip shows no size, tick Display file size information in folder tips under Folder Options, View. To see every folder on a drive sized at once, use a disk space analyzer instead of checking them one by one.
Open any folder in File Explorer and switch to Details view. The Size column shows a number for every file and nothing for every folder. It has been that way since Windows 95 and it still is in Windows 11. People assume a setting is missing. There is not one. Explorer does not size folders on purpose.
This guide gives the four ways Windows offers to get a folder's size anyway and explains why the column stays blank. Then it shows the one method that sizes every folder on the drive in a single pass, which is what you want when the real question is where the space went.
Why Does Windows Explorer Not Show Folder Sizes?
A file's size is stored right next to its name, so Explorer can print it without opening anything. A folder's size is not stored anywhere. To know it, Windows has to walk into the folder, read the size of every file, step into every subfolder and add it all up. For a folder like C:\Windows that means touching hundreds of thousands of entries.
If Explorer did that for every folder in every window you opened, browsing a large drive would crawl. On a network share it would be worse. So Microsoft made a trade: the Size column is instant and only covers files, and folder sizes are worked out on demand when you ask for one. Every method below is a way of asking.
How Do I See Folder Sizes in Windows Explorer?
From the quickest glance to the full picture. The first four are built into Windows. The fifth is for when one number at a time is not enough.
Hover over the folder for a size tip
Rest the mouse pointer on a folder in File Explorer for a second. A small tip appears with its date, the first few files inside and, for folders that are not too large, Size: with the total. Windows stops counting after a short while, so on a huge one the size line is missing. It is the quickest check and needs nothing switched on.
Make sure folder tips are turned on
If hovering shows no size at all, the option may be off. In File Explorer click the three-dot menu, choose Options, open the View tab and tick Display file size information in folder tips. Click OK. On Windows 10 the same box lives under View, Options, Change folder and search options. It is on by default, but some cleanup tools switch it off to speed up browsing.
Open Properties for an exact figure
Right-click the folder and choose Properties. The General tab counts every file inside it and shows Size, Size on disk and the number of files and folders. The count runs live, so with a hundred thousand files inside it takes a while to settle. Select several at once and Properties shows their combined size, which is handy for comparing two or three together.
Use PowerShell when you want a number you can copy
In File Explorer click the address bar, type powershell and press Enter to open a window already in that location. Then run (Get-ChildItem -Recurse -File | Measure-Object -Property Length -Sum).Sum / 1GB. It prints the total in gigabytes. Swap 1GB for 1MB for smaller ones. The old Command Prompt equivalent is dir /s, which lists everything and ends with a total in bytes.
See every folder on the drive sized at once
The steps above give one answer at a time. To see which folders are large across a whole drive, you need a tool that walks the whole tree. Univik Disk Usage Reporter does that in one pass and shows every folder with its size, its share of the drive and a treemap, with the biggest files listed beside them. It is the same job Properties does, done for the whole tree in a single pass. The outcome can be written out to HTML for a browser or to CSV for a spreadsheet.
Size or Size on Disk: Which Folder Size Matters?
The Properties dialog shows two figures and they rarely match. Size is the sum of what is inside the files. Size on disk is the space the drive actually hands over, and NTFS hands it over in clusters, usually 4 KB at a time. A 1 KB file still takes a full 4 KB cluster. Fifty thousand small files can show a Size on disk well above their Size for that reason, while compressed files show the reverse.
When the goal is freeing space, Size on disk is the honest number, because it is what you get back when the contents go. Univik Disk Usage Reporter reports on-disk usage throughout, so the treemap and the ranked list reflect what deleting or moving something would really free.
The folder tip and Properties are fine when you already know which folder to check. The trouble starts when you do not. Nobody right-clicks their way through a terabyte. That is the moment a single scan of the drive earns its keep.
Folder Size Methods Side by Side
What each method costs in time, whether the figure is exact and how much of the drive it covers.
| Method | Speed | Exact size | Scope |
|---|---|---|---|
| Hover folder tip | Instant | Only smaller folders | One folder |
| Properties dialog | Slow on big folders | Yes, exact | One or a selection |
| PowerShell one-liner | Seconds to minutes | Yes, exact bytes | One folder |
| Settings > Storage | Instant | Categories only | Drive summary |
| Univik Disk Usage Reporter | One scan, about a minute per TB | Yes, with treemap and report | Every folder on the drive |
Univik Disk Usage Reporter walks the whole drive once and shows each folder's size and share, a treemap and the largest files with paths. Free to use with no account. Everything runs on your PC, and the result can go to HTML for a browser or CSV for a spreadsheet.
Windows 7 to 11 · local, external and network drives · nothing uploaded
The short version
- The Explorer Size column is for files only. No setting adds folder sizes to it.
- Hover a folder for the tip, or tick Display file size information in folder tips under Folder Options, View.
- Right-click then Properties gives Size and Size on disk. It works on a selection of folders too.
- In PowerShell: (Get-ChildItem -Recurse -File | Measure-Object Length -Sum).Sum / 1GB.
- To size every folder on a drive at once, let Univik Disk Usage Reporter scan it in one go.
Size every folder on your drive, free
Folder Size Questions
About This GuideThis guide is by Leena Taylor Paul of Univik, a Windows utility developer since 2013. Each method was run on Windows 11 and Windows 10, and the folder tips option name and the PowerShell line were checked on both. 22 September 2026. A folder that will not size at all? Support is below.
Reference: Microsoft: storage settings in Windows · Univik Disk Usage Reporter