Security & Surveillance
NVR Storage Reference
TB per camera for 30 days of continuous recording, by resolution and codec, plus the storage-from-bitrate rule and RAID usable-capacity notes. Use alongside the NVR Storage Calculator.
Last updated: July 2026
Terms
- CCTVClosed-Circuit Television
- The general term for a video surveillance/security camera system — cameras that send their picture to a private screen or recorder, not broadcast television.
- H.264video compression standard
- A widely-used method for compressing video so it takes up less storage space and network bandwidth, while keeping reasonable picture quality. The older, more universally-supported of the two common camera codecs.
- H.265video compression standard
- A newer, more efficient version of H.264 — it needs roughly half the storage and bandwidth for the same picture quality, but not every camera or recorder supports it.
- H.265+vendor-enhanced video compression
- A manufacturer-tuned version of H.265 that saves even more space by being smarter about static scenes — it uses less data when nothing is moving in the picture.
- NVRNetwork Video Recorder
- The device (or software) that records and stores video footage from network/IP cameras — the modern, network-based equivalent of an old-fashioned DVR.
- RAID 1Redundant Array of Independent Disks (mirroring)
- Two hard drives that each store an identical, complete copy of everything. If one drive fails, the other still has all the data — but you only get to use half of your total drive capacity.
- RAID 5Redundant Array of Independent Disks, level 5
- A group of three or more hard drives that spreads data and backup information across all of them, so the array survives any single drive failing. You lose the storage space of one drive to this protection — the rest is usable.
- RAID 6Redundant Array of Independent Disks, level 6
- Like RAID 5, but it can survive two drives failing at the same time instead of just one — at the cost of losing two drives' worth of storage space instead of one.
TB per Camera per 30 Days (Continuous)
Storage per camera for 30 days of continuous recording at 30 fps, medium scene complexity — the same bitrate baseline as the IP Camera Bandwidth Calculator, converted with the 10.8 GB/day-per-Mbps rule.
| Resolution | H.264 | H.265 | H.265+ |
|---|---|---|---|
| 2MP (1080p) | 1.30 TB | 0.65 TB | 0.39 TB |
| 4MP | 2.59 TB | 1.30 TB | 0.78 TB |
| 5MP | 3.24 TB | 1.62 TB | 0.97 TB |
| 8MP (4K) | 5.18 TB | 2.59 TB | 1.56 TB |
For N cameras, multiply the per-camera value by N. For a different retention period, scale linearly (e.g. halve for 15 days, double for 60 days).
The Storage-from-Bitrate Rule
GB/day = Mbps × 10.8 × (recording hours ÷ 24) × recording-mode factor
Raw TB (retention) = GB/day × retention days ÷ 1000
10.8 GB/day per Mbps is a field-standard planning constant (1 Mbps continuous ≈ 10.8 GB of footage per day). Recording mode scales it further: continuous = 100%, motion-only ≈ 40% (a ~60% saving) — treat motion-only as a space-saving buffer, not a sizing strategy for critical areas.
RAID Usable-Capacity Notes
| RAID level | Usable fraction | Notes |
|---|---|---|
| None | 100% | No redundancy — a single drive failure loses all footage |
| RAID 1 (mirror) | 50% | Full copy on a second drive; simplest redundancy |
| RAID 5 | (N−1)/N | Tolerates one drive failure; N = drives in the array |
| RAID 6 | (N−2)/N | Tolerates two drive failures; extra rebuild safety margin |
Buy raw capacity to cover your required footage after dividing by the usable fraction — e.g. 6.9 TB required raw at RAID 5 with 4 drives means the array's total raw capacity (drives × size) must reach 6.9 TB before the RAID overhead, not after.
Frequently Asked Questions
How is storage linked to bandwidth?
Storage is bitrate × time. The same per-camera Mbps model as the IP Camera Bandwidth Calculator feeds directly into the 10.8 GB/day-per-Mbps rule, over your recording hours and retention period.
Does RAID reduce my usable space?
Yes — RAID 1 halves it, RAID 5 loses one drive's worth across the array, RAID 6 loses two. Buy raw capacity accordingly.
Should I size for motion-only recording?
Design to continuous for critical areas. Motion-only saves real space but is a buffer against running out of storage, not a guaranteed capture strategy.