IP camera bandwidth & storage calculator
Size the NVR before you buy the cameras: enter how many cameras, what resolution and codec, and how long you keep footage. You get total ingest bandwidth, storage for your retention window, and how many drives that is. Preset bitrates are the mainstream vendor recommendations; override with your camera's actual spec when you know it.
Bitrate reference table
| Resolution | H.264 typical | H.265 typical | GB/day/camera (24h, H.265) |
|---|---|---|---|
| 1080p / 2MP | 4 Mbps | 2 Mbps | ~21 GB |
| 4MP | 8 Mbps | 4 Mbps | ~42 GB |
| 5MP | 6 Mbps | 3 Mbps | ~32 GB |
| 4K / 8MP | 16 Mbps | 8 Mbps | ~84 GB |
Bitrates are the mainstream vendor recommendations (Hikvision, Dahua, Reolink spec sheets) for 15–20 fps; a busy scene can spike above them. Storage math: GB/day = Mbps ÷ 8 × 86,400 ÷ 1024, plus ~10% file-system and index overhead in the calculator's totals.
What the bandwidth number is for
Total ingest tells you three things: whether the NVR's rated throughput is enough (most consumer NVRs ingest 80–160 Mbps), whether your switch uplink survives (a 16-camera H.264 4MP wall needs >1 Gbps — consider 2.5G/10G or two switches), and whether remote viewing over the internet will work (uplink = sub-stream × viewers, not the main stream).
Drives: capacity is not the whole story
NVRs and surveillance drives are a 24/7 sequential-write workload — pick surveillance-class drives (SkyHawk, Purple, SkyHawk AI) sized so the array isn't above ~80% full at end-of-retention, and remember RAID mirrors cost double. For which NVR platforms let you bring your own drives and third-party ONVIF cameras, see the NVR compatibility matrix; for the camera side, third-party camera policies matter more than storage math.
FAQ
How is CCTV storage calculated?
Storage per camera per day (GB) = bitrate (Mbps) ÷ 8 × 86,400 seconds ÷ 1024. Multiply by camera count, recording hours and retention days, then add ~10% overhead. Example: one 4 Mbps 1080p H.264 camera recording continuously uses ~42 GB/day; eight of them for 30 days is ~10 TB.
How much bandwidth do IP cameras use?
A 1080p (2MP) H.264 camera streams around 4 Mbps main plus ~0.5–1 Mbps sub-stream; the same camera in H.265 is roughly half. 4MP runs ~8 Mbps (H.264) / 4 Mbps (H.265), and 4K/8MP ~16 / 8 Mbps. Total NVR ingest = cameras × (main + sub) bitrate.
H.264 or H.265 for my NVR?
H.265 halves storage and bandwidth at the same quality, and every mainstream camera and NVR sold today supports it. Use H.264 only when something old in the chain (a browser plugin, an old NVR firmware, a low-power client) cannot decode H.265. Mixing is fine per-camera.
How many TB do I need for 8 cameras 30 days?
It depends on resolution and recording mode. Use the calculator above — as a reference point, 8× 4MP H.265 cameras at 4 Mbps recording continuously need ~10 TB for 30 days; the same setup on motion-only (~25% of the time) needs ~2.5 TB.