Recording days depend on the number of cameras, resolution, compression (H.265 takes less space than H.264), frame rate and whether recording is continuous or event-based. A simple estimate: each Mbps of video recorded non-stop takes about 10.8 GB a day. In Spain, footage must generally be deleted within one month.
What affects storage
- Resolution and frame rate: more detail and smoothness take more space.
- Compression: H.265 and its smart variants greatly reduce size compared with H.264.
- Scene: a busy street takes more than an empty warehouse.
- Recording mode: continuous, event-only or mixed.
- Dual stream: some installations also record a lighter second stream.
How to estimate
Each camera’s real stream is shown in its settings and varies with the scene. To size the system, multiply each camera’s space by the number of cameras and add a margin. Event recording needs far less space, but only stores what the camera detects.
| Video stream | Space per day | Space over 30 days |
|---|---|---|
| 1 Mbps | ≈ 10.8 GB | ≈ 324 GB |
| 2 Mbps | ≈ 21.6 GB | ≈ 648 GB |
| 4 Mbps | ≈ 43.2 GB | ≈ 1.3 TB |
| 8 Mbps | ≈ 86.4 GB | ≈ 2.6 TB |
Which disk to use
- Surveillance-specific disks designed for continuous writing day and night.
- Several disks or redundancy when footage is critical, so a single failure does not lose it.
- Recorder in a ventilated, protected place, ideally with a UPS.
- Periodic checks of disk health and that recording is working.
Retention period
Spanish data protection law requires video surveillance footage to be deleted within one month of capture, unless it must be kept to prove an incident and handed to the authorities. We configure the recorder to overwrite automatically within that period.
CCTV storage calculator
Work out how many terabytes your recorder needs from the cameras, quality and days of recording. Results update as you change any value.
- Recording bandwidth
- Space per day
- Total space
- Drive capacity needed
Recommendation:
Indicative estimate. Actual space depends on the scene, night lighting and each camera’s settings. Capacity needed includes 10 % for formatting and file system.