Check folder size on C:\temp folder

$mt_measure_folder = Get-ChildItem "C:\temp" | Measure-Object -Property length -sum
$mt_measure_folder.Sum/1MB

Check folder size under current folder

$mt_folder_list = @()

$mt_folders = Get-ChildItem -Directory 

foreach ($mt_folder in $mt_folders)
{
$mt_folder.Name
$mt_measure = Get-ChildItem $mt_folder -Recurse -Force | Measure-Object -Property length -sum -ErrorAction SilentlyContinue

$mt_folder_list.FolderName = $mt_folder.Name
#$mt_folder_list."Size(MB)" = $mt_measure.sum/1MB

}

Create table to result

$mt_data = @()

$mt_folders = Get-ChildItem -Directory

foreach ($mt_folder in $mt_folders)
{

$mt_row = "" | Select-Object Folder_Name, Size_MB

$mt_measure = Get-ChildItem $mt_folder -Recurse -Force -ErrorAction SilentlyContinue | Measure-Object -Property length -sum -ErrorAction SilentlyContinue

$mt_row.Folder_Name = $mt_folder.Name

$mt_row.Size_MB =[decimal]("{0:N2}" -f ($mt_measure.sum/1mb))


$mt_data += $mt_row

}

$mt_data