We have calculated approximate size of disk required for Hikvision CCTV systems. you can also download Hikvisions space calculator by clicking here.
This chart shows approximate hard drive size required for 4, 2MP cameras using the H264 video compression and recorder set to record continuously 24/7. PFS stands for frames per second which is like pictures per second.
For H265 compression systems, the space required is halved. All NVR except DS-76xxNI-Ex and DS-71xxx now support H265 recording