How to Calculate CCTV Storage: A Complete Guide

Accurate storage estimation is the backbone of any CCTV system design. Underestimating storage leads to lost footage and compliance failures, while overestimating wastes budget on unnecessary hardware. The key variables are camera resolution, frame rate, compression codec, recording schedule, and retention period.

Resolution has the largest impact on storage consumption. A 2MP (1080p) camera generates roughly 5–8 GB per day at 15 FPS with H.264 compression, while a 4K (8MP) camera can produce 25–40 GB under the same conditions. Upgrading to H.265 (HEVC) compression typically reduces storage by 30–50% compared to H.264, making it the preferred codec for modern deployments.

Recording schedule and motion detection settings also play a critical role. Continuous 24/7 recording demands far more storage than motion-triggered recording, which can reduce write volume by 50–70% in low-traffic areas. Combining scheduled recording with motion-based triggers allows engineers to optimize storage without sacrificing coverage during critical hours.

Retention policies vary by regulation and industry. Banks may require 90 days of footage, while retail environments typically keep 30 days. RAID configuration adds overhead—RAID 5 sacrifices one disk for parity, while RAID 6 sacrifices two—but provides essential redundancy. Always factor in a 15–20% overhead for filesystem and RAID when sizing your storage array.

Use our free CCTV Storage Calculator to estimate your exact requirements based on camera count, resolution, codec, and retention period. The tool provides instant results including total terabytes needed and recommended hard drive count.