PowerShell - Get List Size

Following is the PowerShell script to get the size of a SharePoint list by calculating the size of the attachments for all items in a list:

function GetListSize($List)
{
    [long]$listSize = 0
    $allAttachmentsFolder = $List.RootFolder.SubFolders["Attachments"]

    foreach ($listItem in $List.Items)
    {                   
        $listItemAttachments = $listItem.Attachments
        $attachmentsFolder = $allAttachmentsFolder.SubFolders[$listItem.ID]
        foreach($file in $listItemAttachments) 
        {            
            $listSize += $attachmentsFolder.Files[$file].Length
        }
    }

    $totalInMb = ($listSize/1024)/1024
    $totalInMb = "{0:N2}" -f $totalInMb

    return $totalInMb    
}

Ref: http://sharepoint.stackexchange.com/questions/12652/get-total-size-of-attached-files-on-all-list-items-in-sharepoint-2007with-powers