Storage depends on data rate over time. Multiply cameras by average bitrate, convert bits to bytes, then multiply by recording seconds and retention days. Resolution alone is not enough because codec, frame rate, scene motion, quality settings and variable bitrate change actual data use.
Estimate CCTV recording storage
Enter the configured average bitrate—not resolution alone. Motion, scene detail, codec, frame rate and recorder settings can change actual use.
Formula and units
Bytes per day = cameras × megabits per second × 1,000,000 ÷ 8 × recording hours × 3,600. Retention bytes = bytes per day × days. The page displays decimal GB and TB, matching the common drive-capacity convention.
The extra 20% is a planning margin, not a universal requirement. Recorder overhead, event metadata, file-system use and real bitrate behaviour vary. Verify the recorder's supported drive type, size, bay count and retention result before procurement.
Get a realistic average bitrate
- Use the recorder or camera stream configuration rather than a resolution guess.
- Measure representative busy and quiet scenes when variable bitrate is enabled.
- Account separately for main and secondary streams if both are recorded.
- Adjust hours for scheduled or event recording, while planning for unexpected continuous activity.
- Keep required incident footage protected from automatic overwrite under the applicable policy.
Sources and further reading
Technical statements were reviewed against these references. External pages may change after our review date.
- Surveillance Storage Calculator — Seagate