Get-DirectorySize

Get-DirectorySize.psm1

Function ConvertTo-HumanReadable([long] $size)
{
    if($size -lt 0) { return "Failed" }

    if($size -ge 1GB){
        "{0,7:#,##0.0}G" -F ($size/1GB)
    }elseif($size -ge 1MB){
        "{0,7:#,##0.0}M" -F ($size/1MB)
    }elseif($size -ge 1KB){
        "{0,7:#,##0.0}K" -F ($size/1KB)
    }else{
        "{0,7:#,##0.0}B" -F $size
    }
}

Function Get-DirectorySize([string] $tartgetFolder, [switch]$OrderBySize, [switch]$NonFso, [switch]$AddTotal)
{
    begin{
        $fso = New-Object -ComObject Scripting.FileSystemObject 
        $p = 0
        $pmax = (Get-ChildItem $tartgetFolder).Count
        $order = if($OrderBySize){'SizeByte'}else{'Name'}
        $sizeTotal, $filesTotal, $foldersTotal = 0, 0, 0
    }
    process{
        Get-ChildItem $tartgetFolder|
        %{
            Write-Progress -Activity "Progress" -Status $_ -PercentComplete ($p/$pmax*100)
            $p += 1
            if($_ -is [System.IO.DirectoryInfo]){
                if($NonFso){
                    $byteSize = (Get-ChildItem -Force $_.FullName -Recurse|Measure-Object -Property Length -Sum).Sum
                }else{
                    $byteSize = if($fso.GetFolder($_.FullName).size -ge 0){ [long]$fso.GetFolder($_.FullName).size }else{ -1 }
                }
                $files = (Get-ChildItem $_.FullName -File -Recurse -Force).Count
                $folders = (Get-ChildItem $_.FullName -Directory -Recurse -Force).Count
            }else{
                $byteSize = $_.Length
                $files = 1
                $folders = 0
            }
            $sizeTotal += $byteSize
            $filesTotal += $files
            $foldersTotal += $folders
            New-Object PSObject -Property @{
                Name = $_.Name
                SizeByte = $byteSize 
                Size = ConvertTo-HumanReadable $byteSize 
                Files = $files
                Folders = $folders
            }
        }|Sort $order|Format-Table Name,Size,SizeByte,Files,Folders -AutoSize 
    }
    end{
        if($AddTotal){
            "Total Size:      {0,15}" -f (ConvertTo-HumanReadable $sizeTotal)
            "Total Size(byte):{0,15}" -f $sizeTotal
            "Total Files:     {0,15}" -f $filesTotal
            "Total Folders:   {0,15}" -f $foldersTotal
        }
    }
}

Export-ModuleMember -Function Get-DirectorySize