Probably, this is what you were looking for!!!

select

Name as 'Database'

, Filename as 'Location'

, convert(numeric(10,2),round(a.size/128.000,2)) as SizeMB

, convert(numeric(10,2),round(fileproperty(a.name,'SpaceUsed')/128.000,2)) as UsedSpaceMB

, convert(numeric(10,2),round((a.size-fileproperty(a.name,'SpaceUsed'))/128.000,2)) as FreeSpaceMB

, convert(numeric(10,4),round(fileproperty(a.name,'SpaceUsed')/128.000,2)/1000) as UsedSpaceGB

, convert(numeric(10,4),round((a.size-fileproperty(a.name,'SpaceUsed'))/128.000,2)/1000) as FreeSpaceGB

from dbo.sysfiles a