How to Get Folder Size in PowerShell (Including Subfolders)

To get a folder’s size in PowerShell, list every file under it with Get-ChildItem -Recurse and add up their Length values with Measure-Object. The result is in bytes, so divide by 1MB or 1GB:

$folder = 'C:\psfaqs\CompanyData'
$size   = (Get-ChildItem -Path $folder -File -Recurse -Force | Measure-Object -Property Length -Sum).Sum

"{0:N2} MB" -f ($size / 1MB)

Output:

91.50 MB

A folder doesn’t store its own size, so PowerShell has to add up the files, just like the Properties window in File Explorer does. The number matches the Size value there, not Size on disk.

My test folder here is a small copy of a department share, with Finance, HR and Marketing subfolders. I ran each example in PowerShell 7.6 and Windows PowerShell 5.1, and both gave the same results.

Why -Recurse and -Force matter

Leave out -Recurse and you only count the files directly inside the folder. For my test folder, that’s a single readme file:

$size = (Get-ChildItem -Path C:\psfaqs\CompanyData -File | Measure-Object -Property Length -Sum).Sum
"{0:N2} KB" -f ($size / 1KB)

Output:

2.00 KB

-Force is the one people forget. Without it, Get-ChildItem skips hidden and system files, so your total comes in lower than File Explorer’s:

$folder = 'C:\psfaqs\CompanyData'

$visible = (Get-ChildItem -Path $folder -File -Recurse | Measure-Object -Property Length -Sum).Sum
$all     = (Get-ChildItem -Path $folder -File -Recurse -Force | Measure-Object -Property Length -Sum).Sum

"Without -Force: {0:N2} MB" -f ($visible / 1MB)
"With -Force:    {0:N2} MB" -f ($all / 1MB)

Output:

Without -Force: 81.50 MB
With -Force:    91.50 MB

The missing 10 MB is a hidden cache file in the Marketing folder. On real servers, hidden files like caches and thumbnails can add up to gigabytes.

How do I get the size of each subfolder?

To see where the space goes, measure each subfolder on its own and sort the results. This is the report I run most often on a full file share:

Get-ChildItem -Path C:\psfaqs\CompanyData -Directory | ForEach-Object {
    $files = Get-ChildItem -Path $_.FullName -File -Recurse -Force
    [pscustomobject]@{
        Folder = $_.Name
        Bytes  = ($files | Measure-Object -Property Length -Sum).Sum
        Files  = @($files).Count
    }
} | Sort-Object -Property Bytes -Descending |
    Format-Table -Property Folder, Files,
        @{ Name = 'Size (MB)'; Expression = { '{0:N2}' -f ($_.Bytes / 1MB) }; Align = 'Right' }

Output:

Folder    Files Size (MB)
------    ----- ---------
Marketing     3     57.50
Finance       3     32.50
HR            2      1.50

I format the size as text only in Format-Table at the end. Sorting uses the raw bytes, so 9.5 MB never sorts above 32.5 MB.

Find the largest files

Once you know the biggest folder, find the files taking up the space:

Get-ChildItem -Path C:\psfaqs\CompanyData -File -Recurse -Force |
    Sort-Object -Property Length -Descending |
    Select-Object -First 3 |
    Format-Table -Property Name,
        @{ Name = 'Size (MB)'; Expression = { '{0:N2}' -f ($_.Length / 1MB) }; Align = 'Right' }

Output:

Name                 Size (MB)
----                 ---------
campaign-video.mp4       45.00
prior-year-close.zip     20.00
video-cache.tmp          10.00

For more on sorting and filtering file lists, see how to use Get-ChildItem in PowerShell.

Convert bytes to MB, GB and TB

PowerShell has built-in size constants: 1KB, 1MB, 1GB, 1TB and 1PB. Divide by one of them, then round the result with -f or [math]::Round():

$bytes = 10737418240

$bytes / 1GB
"{0:N2} GB" -f (4850000000 / 1GB)
[math]::Round(4850000000 / 1GB, 2)

Output:

10
4.52 GB
4.52

"{0:N2}" -f returns text with thousands separators, which is best for display. [math]::Round() returns a number you can still sort or compare.

Why does a 500 GB drive show as 465 GB?

PowerShell’s constants are binary, so 1GB means 1,073,741,824 bytes. Drive makers use 1,000,000,000 bytes per GB. Same bytes, different unit:

$bytes = 500000000000    # what the box says: 500 GB

"1GB in PowerShell = {0:N0} bytes" -f 1GB
"A 500 GB drive in Windows = {0:N2} GB" -f ($bytes / 1GB)

Output:

1GB in PowerShell = 1,073,741,824 bytes
A 500 GB drive in Windows = 465.66 GB

Windows and PowerShell use the binary unit, so a “500 GB” drive always shows about 465 GB. Nothing is missing.

A function that picks the right unit

For reports, it’s nicer to show each size in the unit that fits. This small function does that:

function Format-FileSize {
    param([double]$Bytes)
    switch ($Bytes) {
        { $_ -ge 1TB } { return '{0:N2} TB' -f ($_ / 1TB) }
        { $_ -ge 1GB } { return '{0:N2} GB' -f ($_ / 1GB) }
        { $_ -ge 1MB } { return '{0:N2} MB' -f ($_ / 1MB) }
        { $_ -ge 1KB } { return '{0:N2} KB' -f ($_ / 1KB) }
        default        { return "$_ bytes" }
    }
}

Format-FileSize 512
Format-FileSize 1536
Format-FileSize 95682150
Format-FileSize 3221225472

Output:

512 bytes
1.50 KB
91.25 MB
3.00 GB

Paste it into your script or profile and call it with any byte count, such as a folder total or a file’s Length.

A faster option for big folders

On folders with hundreds of thousands of files, Get-ChildItem gets slow, because it builds a PowerShell object for every file. The Windows Scripting.FileSystemObject COM object can return a folder’s size in one call:

$fso    = New-Object -ComObject Scripting.FileSystemObject
$folder = $fso.GetFolder('C:\psfaqs\CompanyData')

"{0:N2} MB" -f ($folder.Size / 1MB)

Output:

91.50 MB

It includes hidden files, so it matches the -Force total. The catch shows up when any subfolder denies you access. Here’s the same call after I locked the Legal folder:

$folder = (New-Object -ComObject Scripting.FileSystemObject).GetFolder('C:\psfaqs\CompanyData')
"Size: [$($folder.Size)]"

Output:

Size: []

No size and no error, just an empty value. A script th