CCTV Storage & Retention Calculator

Assumptions

• Bitrate is the average recorded bitrate per camera. TB uses decimal capacity: 1 TB = 10^12 bytes.

Important notes

• Motion-triggered recording, variable bitrate peaks, additional streams, RAID and hot spares can change the final disk configuration. The overhead percentage is a planning allowance, not an automatic RAID calculation.

Standards and sources

• ONVIF Streaming Specifications

Verified: 2026-09-05

Calculation method

Daily capacity (TB) = cameras × average bitrate (Mbps) × 10^6 × hours per day × 3600 / 8 / 10^12. Usable capacity = daily capacity × retention days. Recommended raw capacity = usable capacity × (1 + storage overhead % / 100).

Worked example

Planning example: 32 cameras at an average 4 Mbps, recording 24 hours per day for 30 days, with 20% overhead. Daily capacity is 1.3824 TB; usable capacity is 41.472 TB; recommended raw capacity is 49.7664 TB. TB is decimal, not TiB.

Scope and limitations

Overhead is an entered planning allowance; the tool does not derive RAID or hot-spare capacity. Check actual variable bitrate peaks, extra streams, recording schedules and disk layout separately. This example is not a field measurement.