Ready or Not System Requirements
Minimum
OSWindows
ProcessorIntel Core i5-4430 / AMD FX-6300
Memory8 GB
GraphicsNVIDIA GTX 960 / AMD Radeon R7 370
Storage60-90 GB (has grown via updates)
Recommended
OSWindows
ProcessorIntel Core i5-7500K / AMD Ryzen 5 1600
Memory8 GB
GraphicsNVIDIA GTX 1060 / AMD Radeon RX 580
Storage60-90 GB (has grown via updates)
Source: Official Steam store page — corroborated across multiple outlets