Official specs from Steam

Crusader Kings III system requirements

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

Minimum

Note	Requires a 64-bit processor and operating system
OS	Windows® 10 Home 64 bit
Processor	Intel Core i5-750 \| AMD FX 4300
Memory	8 GB RAM
Graphics	NVIDIA GeForce GTX 660 \| AMD Radeon HD 7870 \| Intel Arc A310 \| Intel Iris Plus G7 \| AMD Radeon Vega 11
Storage	20 GB available space

OS	macOS Sequoia v15 or newer
Processor	Intel Core i5-6500 or newer \| Apple M1 or newer
Memory	8 GB RAM
Graphics	AMD Radeon R9 M380 2GB or better (for Intel systems) \| Intel Iris Plus G7 \| AMD Radeon Vega 11 \| Apple M1 integrated GPU
Storage	20 GB available space

What graphics card do I need for Crusader Kings III?

How much RAM does Crusader Kings III need?

Crusader Kings III needs 8 GB RAM at minimum, 16 GB RAM recommended.

How big is Crusader Kings III?

Crusader Kings III requires 20 GB available space.

Does Crusader Kings III run on Mac or Steam Deck/Linux?

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

Note	Requires a 64-bit processor and operating system
OS	Windows® 10 Home 64 bit or Windows® 11
Processor	Intel Core i5-8400 \| AMD Ryzen 5 1600X
Memory	16 GB RAM
Graphics	NVIDIA GeForce GTX 970 \| AMD Radeon RX 480 \| Intel Arc A580
Storage	20 GB available space