Windows
OS: Windows 7 SP1+ (64-bit*)
Processor: 1.6GHz dual-core
Memory: 1 GB RAM
Graphics: 512 MB Video Memory, Shader Model 4.0
DirectX: Version 11
Storage: 2 GB available space
Additional Notes: * A 64-bit version of Windows is required for Universe Sandbox updates after November 2018. Users on 32-bit systems can still run previous versions.
Mac
OS: macOS 10.11+
Processor: 1.6GHz dual core
Memory: 1 GB RAM
Graphics: OpenGL, 512 MB Video Memory
Storage: 1 GB available space
Linux
OS: Ubuntu 12.04+, SteamOS+
Processor: 1.6GHz dual core
Memory: 1 GB RAM
Graphics: OpenGL, 512 MB Video Memory
Storage: 1 GB available space
Additional Notes: Officially supports the same Linux distributions supported by Unity. Other distributions can and will work, but they may require a bit of configuration and tinkering.