Express Edition (Free, but Limited Performance)
Express Edition is the free version of SQL Server, but database sizes and hardware capacity are limited. Management Studio is fully functional though.
Expand the Details section on these pages to see which parts you want to download:
- Download SQL Server 2016 Express Edition Free
- Download SQL Server 2014 Express Edition Free
- Download SQL Server 2012 SP2 Express Edition Free
Developer Edition (Free, and Unlimited Performance)
As of SQL Server 2014, Developer Edition is now free. It has all the capabilities of Enterprise Edition, but you’re not allowed to use it for production purposes.
Download it after registering for Visual Studio Dev Essentials. You may have to go through a registration process, and then come back and hit this link again to get directly to the download.