You can use the following simple Powershell command to get the SID of an Active Directory user:
Get-ADUser [username]
This will give the following output:
DistinguishedName : CN=[username]U=Accounts,OU=Resources,DC=ad,DC=local Enabled : True GivenName : User1 Name : User1 ObjectClass : user ObjectGUID : 0e11261d-1880-46b7-8dcd-37d04d7f89ed SamAccountName : user1 SID : S-1-5-21-3314419218-4032226268-1344692420-33978 Surname : LastName UserPrincipalName : user1@ad.local
Retrieve the SID from this line:
SID : S-1-5-21-3314419218-4032226268-1344692420-33978
I hope this helped you!