IP Camera / NVR Storage Calculator
Estimate hard-drive storage for a security camera system from camera count, resolution, frame rate, recording mode, and retention days. Free NVR planning tool.
Estimate based on constant bitrate; real footage varies with scene motion and compression. High-detail or busy scenes run higher. Buy surveillance-rated drives (WD Purple, Seagate SkyHawk) — they're tuned for 24/7 sequential writes from many streams, unlike desktop drives. Leave headroom so the NVR isn't constantly overwriting at 100% full.
What actually drives storage
It's bitrate × time, not megapixels directly. A camera's bitrate (Mbps) is the real number — resolution and frame rate influence it, but so do the codec and scene complexity. The two biggest levers are recording mode (continuous 24/7 vs. motion-only can cut storage by two-thirds) and retention (how many days you keep footage — often set by insurance or policy). Switching from H.264 to H.265/HEVC roughly halves the storage for the same quality if your cameras and NVR support it.
Buy the right drives
Use surveillance-rated drives (WD Purple, Seagate SkyHawk), not desktop drives — they're built for 24/7 sequential writes from many simultaneous streams. Size with headroom so the NVR isn't perpetually overwriting at 100% full. More on planning a system: business video surveillance basics.