Get Folder Size of Shared Folders and Export to CSV File

First we need to get and export all shared folders.

Get-SmbShare | select name, path |Export-Csv "C:\smbsharelist.csv" -NoTypeInformation -Encoding UTF8 

Then we import the csv and run the script below to calculate folder size in GB

Import-Csv -Path "C:\smbsharelist.csv" | ForEach-Object{
$path =$_.Path
$name =$_.Name 
$path, "{0} GB" -f ((Get-ChildItem -force $path -Recurse  -ErrorAction SilentlyContinue| Measure-Object -Property Length -Sum -ErrorAction Stop).Sum / 1GB) 
} | Set-Content "C:\SizesOfSharedFoldersInGB.csv" -Encoding UTF8

Same script that calculates folder sizes in MB

Import-Csv -Path "C:\smbsharelist.csv" | ForEach-Object{
$path =$_.Path
$name =$_.Name 
$path, "{0} MB" -f ((Get-ChildItem -force $path -Recurse  -ErrorAction SilentlyContinue| Measure-Object -Property Length -Sum -ErrorAction Stop).Sum / 1MB) 
} | Set-Content "C:\SizesOfSharedFoldersInMB.csv" -Encoding UTF8