Estimate CCTV storage without promising a retention period

CCTV storage depends on the recorded bitrate and duration, not only the camera count. Use a calculation to estimate capacity, then verify actual recording behaviour and usable retention in the installed system.

Start with a transparent calculation

For continuous recording, estimated decimal gigabytes = combined recorded bitrate in megabits per second × 86,400 seconds per day × days ÷ 8 ÷ 1,000. This is a planning calculation before storage overhead, reserved capacity or other system constraints.

Illustrative example: four cameras averaging 2 Mb/s each produce a combined 8 Mb/s. Seven days gives 8 × 86,400 × 7 ÷ 8 ÷ 1,000 = 604.8 GB. The camera count, bitrate and period are fictional assumptions, not a Foxbyte installation specification.

Explore the assumptions

The calculator uses the same simple continuous-recording formula. It does not choose a recorder, prescribe a retention policy or guarantee that a labelled drive capacity will deliver the selected period.

Understand what can change the result

Factor	Why the estimate can differ
Variable bitrate	Scene detail, movement and encoding can change the average.
Recording schedule	Continuous and event-based recording produce different totals.
Settings	Resolution, frame rate and compression affect the recorded stream.
Capacity overhead	Usable storage can differ from the labelled capacity.
System limits	Recorder throughput, camera support and other constraints need checking.
Retention behaviour	Actual deletion or overwrite behaviour depends on the configured system.

Choose the period as a business and handling decision

The required recording period should follow the purpose and applicable handling requirements, not simply the largest disk available. Identify who approves retention, who can retrieve footage and how an incident affects the normal handling process.

For personal information in Kenya, the operator should review the relevant legal requirements with appropriate advice. This article does not prescribe a universal lawful CCTV retention period. A storage calculation cannot make that decision for the organisation.

Verify after commissioning

• Record the configured camera and recording settings.
• Observe actual usage over a representative period.
• Check the oldest available footage against the expected behaviour.
• Test playback and a representative authorised export.
• Review changes when cameras or settings are added.

Keep the estimate and observed result separate in the handover record. A successful live view does not prove the required recording history is available, and a capacity estimate should not be labelled a measured retention result.