Get Site Content Size in SharePoint 2013

To Get Site Content Size in SharePoint using Powers hell run the following command :

Get-SPSite http://sps2013 | Select Url, @{Label="Size";Expression={$_.usage.Storage/1MB}}

To Get all Site Collections in the Farm and sorts them from largest to smallest based on content size run the following command:

Get-SPSite | Select Url, @{Label="Size";Expression={$_.usage.Storage/1MB}} 

| Sort-Object -Descending -Property "Size"