Find the largest folders on a drive with PowerShell

The disk is full and the Properties dialog shows one folder at a time. This script measures every top-level folder under a path and prints the largest ones with their sizes. Point it at a drive root, a user profile or a project folder.

The script

[CmdletBinding()]
param(
    [string]$Path = 'C:\',
    [int]$Top = 15
)

if (-not (Test-Path -LiteralPath $Path -PathType Container)) {
    Write-Error "Folder not found: $Path"
    exit 1
}

$drive = (Get-Item -LiteralPath $Path).PSDrive
if ($null -ne $drive.Used) {
    $usedGB = [math]::Round($drive.Used / 1GB, 1)
    $freeGB = [math]::Round($drive.Free / 1GB, 1)
    Write-Host "Drive $($drive.Name): $usedGB GB used, $freeGB GB free"
}
Write-Host "Scanning $Path ..."

$results = Get-ChildItem -LiteralPath $Path -Directory -Force -ErrorAction SilentlyContinue |
    ForEach-Object {
        Write-Verbose "Measuring $($_.FullName)"
        $files = Get-ChildItem -LiteralPath $_.FullName -File -Recurse -Force -ErrorAction SilentlyContinue
        $bytes = ($files | Measure-Object -Property Length -Sum).Sum
        [pscustomobject]@{
            Folder = $_.FullName
            Files  = @($files).Count
            SizeGB = [math]::Round(($bytes / 1GB), 2)
        }
    }

$looseBytes = (Get-ChildItem -LiteralPath $Path -File -Force -ErrorAction SilentlyContinue |
    Measure-Object -Property Length -Sum).Sum
$results += [pscustomobject]@{
    Folder = "(files directly in $Path)"
    Files  = @(Get-ChildItem -LiteralPath $Path -File -Force -ErrorAction SilentlyContinue).Count
    SizeGB = [math]::Round(($looseBytes / 1GB), 2)
}

$results |
    Sort-Object SizeGB -Descending |
    Select-Object -First $Top |
    Format-Table -AutoSize

How to run it

.\Get-LargeFolders.ps1
.\Get-LargeFolders.ps1 -Path 'C:\Users\ana' -Top 10
.\Get-LargeFolders.ps1 -Path D:\ -Verbose

Save it as Get-LargeFolders.ps1. A full drive scan takes a minute or two. Run from an elevated prompt to measure folders your account cannot normally read, such as other users’ profiles; otherwise those folders show up smaller than they are because inaccessible files are skipped silently.

How it works

• Get-ChildItem -Directory lists only folders; -File -Recurse then collects every file below each one. -Force includes hidden and system items such as $Recycle.Bin.
• Measure-Object -Sum on Length adds the file sizes. Dividing by the 1GB constant turns bytes into gigabytes.
• -ErrorAction SilentlyContinue keeps access-denied errors from flooding the output. Use -Verbose to see which folder is being measured.
• A separate line counts files that sit directly in the path, so a huge file in the root does not vanish from the picture.
• [pscustomobject] builds one row per folder, which is why the output is a real table you can sort or export.

Variations

# Drill into the biggest folder
.\Get-LargeFolders.ps1 -Path 'C:\Users\ana\AppData\Local'

# Save the table instead of printing it
.\Get-LargeFolders.ps1 -Path C:\ | Out-File folders.txt

# The 20 largest single files under a path
Get-ChildItem C:\Users\ana -File -Recurse -Force -ErrorAction SilentlyContinue |
    Sort-Object Length -Descending | Select-Object -First 20 FullName, @{N='MB';E={[math]::Round($_.Length/1MB)}}

The SizeGB figures are sums of file lengths, so they can be slightly below what Explorer reports as size on disk, and they do not include files you are not allowed to read. For a graphical view of the same data, WinDirStat and TreeSize Free are the usual tools; this script is for when you want the answer in a terminal or a log file.