Command to get size of your SharePoint 2010 site

In MOSS2007 we can get to the STSADM by opening windows command prompt and changing directory to:

 C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\12\BIN

In SharePoint 2010 we can find this at location:

C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\BIN

Now to get the size of your site type the following command on the prompt:

STSADM.exe  -o  enumsites  -url http:// <sitename> 

It will display the size of your site under the tag "StorageUsedMB".

----- Or -----
$siteColl = Get-SPSite "URL of Site Collection"
$siteColl | select @{Name="Size"; Expression={"{0:N2} MB" -f ($_.Usage.Storage/1000000)}}