Official specs from Steam

Terraria system requirements

Minimum and recommended PC specs as listed by the developer on Steam. Native macOS version available. Native Linux build available.

Minimum

OSWindows Xp, Vista, 7, 8/8.1, 10
Processor2.0 Ghz
Memory2.5GB
Hard Disk Space200MB
Video Card128mb Video Memory, capable of Shader Model 2.0+
DirectX®9.0c or Greater

Recommended

OSWindows 7, 8/8.1, 10
ProcessorDual Core 3.0 Ghz
Memory4GB
Hard Disk Space200MB
Video Card256mb Video Memory, capable of Shader Model 2.0+
DirectX®9.0c or Greater

macOS minimum

OSOSX 10.9.5 - 10.11.6
Processor2.0 Ghz
Memory2.5GB
Hard Disk Space200MB
Video Card128mb Video Memory, capable of OpenGL 3.0+ support (2.1 with ARB extensions acceptable

macOS recommended

OSOSX 10.9.5 - 10.11.6
ProcessorDual Core 3.0 Ghz
Memory4GB
Hard Disk Space200MB
Video Card256mb Video Memory, capable of OpenGL 3.0+ support (2.1 with ARB extensions acceptable

FAQ

What graphics card do I need for Terraria?

Minimum: 128mb Video Memory, capable of Shader Model 2.0+. Recommended: 256mb Video Memory, capable of Shader Model 2.0+.

How much RAM does Terraria need?

Terraria needs 2.5GB at minimum, 4GB recommended.

How big is Terraria?

Terraria requires 200MB.

Does Terraria run on Mac or Steam Deck/Linux?

Yes, there is a native macOS version. A native Linux build is available.