Reviewed, sourced guidance
CCTV storage calculator method and limitations
Direct answer
For one group, estimated decimal GB per day equals cameras × Mbps per camera × recorded hours per day × 0.45. Multiply by retention days and divide by 1,000 for decimal TB. A user-selected margin is applied only after the base result.
This page records how the local calculator converts entered stream bitrate and recording time into decimal storage estimates.
Key takeaways
- Model version: 2026-09-24-v1.
- Units are decimal: 1 GB = 1,000 MB and 1 TB = 1,000 GB.
- Every group has its own bitrate, hours and days.
- The margin is user-entered and is not a recommended allowance.
Source review cadence
Every source cited on this site carries a dated check and a recheck trigger, so stale evidence is replaced rather than quietly relied on.
| Source | Last checked | Recheck | Triggers an early review |
|---|---|---|---|
| Seagate UK, video storage calculator for surveillance (observed 2026-09-25; manufacturer tool) | 2026-09-25 | every 180 days | Manufacturer tool, assumptions, model specification or unit presentation changes; A comparison on this site changes |
| Western Digital, surveillance storage estimator and limitations (observed 2026-09-25; manufacturer tool) | 2026-09-25 | every 180 days | Manufacturer tool, assumptions, model specification or unit presentation changes; A comparison on this site changes |
| Hikvision, DS-9616NXI-I8R/VPro NVR data sheet (observed 2026-09-25; model-specific example only) | 2026-09-25 | every 180 days | Manufacturer tool, assumptions, model specification or unit presentation changes; A comparison on this site changes |
| Axis Communications, Bitrate control for IP video (white paper, March 2023; observed 2026-09-27) | 2026-09-27 | every 180 days | Manufacturer tool, assumptions, model specification or unit presentation changes; A comparison on this site changes |
| ICO, storage limitation and retention for surveillance systems (observed 2026-09-25; guidance under review) | 2026-09-25 | every 30 days | Data (Use and Access) Act guidance review changes; Retention guidance or related site claims change |
| ICO, storage limitation principle (observed 2026-09-25; guidance under review) | 2026-09-25 | every 30 days | Data (Use and Access) Act guidance review changes; Retention guidance or related site claims change |
Equation and units
One megabit per second is 1,000,000 bits per second. Dividing by eight converts bits to bytes; multiplying by 3,600 seconds gives 450,000,000 bytes per recorded hour, or 0.45 decimal GB.
Group storage equals that daily amount multiplied by the entered retention days. Group results are added. The optional margin multiplies the combined base estimate by one plus the entered percentage divided by 100.
Sources for this section: Western Digital, surveillance storage estimator and limitations (observed 2026-09-25; manufacturer tool)
What the model does not predict
The tool does not derive bitrate from resolution, frame rate or a codec. It does not estimate motion activity, codec efficiency, network overhead, audio, multiple streams, filesystem use, reserved sectors, redundancy or usable drive capacity.
Manufacturer estimators use their own assumptions. Western Digital explicitly describes its estimator as illustrative and says actual needs vary with the selected system and settings.
Sources for this section: Western Digital, surveillance storage estimator and limitations (observed 2026-09-25; manufacturer tool)Seagate UK, video storage calculator for surveillance (observed 2026-09-25; manufacturer tool)
Choose a method that matches the information you have
This calculator is for a configured average bitrate you can read from the camera or recorder. Seagate lets users set picture size and quality, compression, frame rate, recording hours, motion recording and retention. WD asks for video format, quality and scene activity; it says its result uses WD-determined compression assumptions. These can help explore a system when its measured bitrate is not available, but they remain estimates tied to each manufacturer’s model.
When possible, check the actual stream setting and recording schedule for the device you plan to use, then calculate from those values here. Neither a scenario estimate nor this arithmetic verifies usable disk capacity, recorder compatibility or a suitable retention period.
Sources for this section: Seagate UK, video storage calculator for surveillance (observed 2026-09-25; manufacturer tool)Western Digital, surveillance storage estimator and limitations (observed 2026-09-25; manufacturer tool)
Next steps
- Read the device’s actual configuration before entering values.
- Recheck assumptions when cameras, schedules, firmware or retention needs change.