DB comparer field by field for all tables
There are many free tools - native and opensource available for comparing schema between 2 databases:


Open DBDiff ==> This is on Codeplex and works great.
SQL Admin Studio ==> This is now a free tool.
Hidden Gem from SQL 2005 and up :  tablediff.exe (you can find this in the COM directory of your SQL Server install folder) Compare schemas: Regular or Strict
Powershell - You have to write your own code or build up on existing ones
Since you are using SQL Server 2012, SSDT is also an option.


From my experience, its worth to invest in Redgate's Schema and data compare tools as they have commandline options and they integrate well with Powershell as well.