CCTV Storage Calculator
Calculate the total storage required for your CCTV surveillance system based on camera specifications, recording schedule, and retention period.
Formula
Bitrate per camera (Mbps):
Bitrate = Resolution (MP) × FPS × Codec Factor × Quality Factor × 0.07
Storage per camera per day (GB):
GB/camera/day = Bitrate × 3600 × Hours/day × Motion Factor ÷ 8 ÷ 1024
Total storage (GB):
Total = GB/camera/day × Cameras × Retention Days × (1 + Overhead / 100)
The base constant 0.07 is derived from industry benchmarks where a 2 MP camera at 15 fps with H.265 at high quality produces approximately 2 Mbps. Codec factors: MJPEG = 8×, H.264 = 2×, H.265 = 1×, H.265+ = 0.8× (relative to a normalised baseline).
Assumptions & References
- Bitrate estimates are based on industry-standard benchmarks from Hikvision, Dahua, and Axis camera datasheets.
- H.265 (HEVC) reduces storage by approximately 50% compared to H.264 at equivalent quality (ISO/IEC 23008-2).
- H.265+ / Smart Codec applies additional scene-adaptive compression, reducing bitrate by a further ~20%.
- Motion detection activity factors: 20% assumes a quiet environment; 50% assumes a busy retail or traffic scene.
- A 20% storage overhead accounts for file system metadata, index files, and NVR/DVR operating space.
- HDD recommendations assume single-drive configurations; RAID arrays will require additional capacity.
- Frame rates above 30 fps (e.g. 60 fps) are used for high-speed event capture and significantly increase storage.
- References: IPVM Storage Calculator methodology; Seagate SkyHawk NAS drive sizing guide; IEC 62676-1-1 (CCTV standards).