CCTV Storage Calculator

This calculator uses industry-standard bitrate values based on real-world measurements. Actual storage consumption can vary ±20–40% depending on scene complexity (a busy street generates far more data than an empty corridor), camera quality settings, and ambient lighting. For critical projects, always add a 20–30% buffer above calculated values and verify with test recordings from your actual cameras before final hardware procurement.

H.265+ (also called Smart Codec by Dahua, or H.265 Pro by Hikvision) is a proprietary enhancement to standard H.265 that uses scene analysis to aggressively compress static background areas while maintaining full quality on moving objects. In low-motion environments (parking lots, empty corridors, perimeter fencing), H.265+ can reduce storage consumption by 50–70% compared to standard H.265. In high-motion scenes (busy intersections, retail floors), the gain is less dramatic — typically 20–35%. It only works with compatible cameras and NVRs from the same manufacturer.

RAID 6 is recommended for CCTV storage arrays with 8+ drives. With large HDDs (8–16TB), a RAID 5 rebuild after a drive failure can take 24–72 hours — during which a second failure causes total data loss. RAID 6 tolerates two simultaneous failures, making it far safer during rebuild windows. For smaller arrays (4–6 drives), RAID 5 with a hot spare is a reasonable compromise. For critical infrastructure (banks, casinos, airports), dual-recording to two separate storage servers without RAID dependency is preferable.

DVRs (Digital Video Recorders) connect to analog cameras via coaxial cable — storage is internal to the DVR unit, limited to the DVR's built-in HDD bays (typically 4–8 drives). NVRs (Network Video Recorders) connect to IP cameras over ethernet — storage can be internal or on a separate network-attached storage (NAS) or dedicated storage server, enabling much larger capacities. Modern IP camera deployments using VMS platforms like Dahua DSS Pro use dedicated storage server nodes separate from the management server, allowing hundreds of terabytes of storage capacity.

In motion-triggered mode, cameras only record when motion is detected. Storage savings depend heavily on actual scene activity: a busy retail entrance might record 60–80% of the time (modest savings), while a rarely-accessed server room might record only 5–15% of the time (massive savings). This calculator uses a configurable motion activity percentage — use 20–40% for typical indoor environments, 40–60% for moderate outdoor scenes, and 60–80% for busy areas. Always verify with actual camera motion statistics before sizing final storage.

Always use surveillance-grade HDDs, not desktop or NAS drives. Leading options are Seagate SkyHawk (up to 20TB), Western Digital WD Purple (up to 18TB), and Toshiba S300 (up to 20TB). These drives are specifically engineered for 24/7 write cycles, high-vibration multi-drive enclosures, and the sequential write pattern of video recording. Desktop drives used in NVRs typically fail within 6–18 months under continuous recording load. For enterprise deployments with 16+ drives, consider SAS drives for higher reliability and hot-swap capability.