CCTV Storage and Bandwidth Calculator
Will the recorder handle these cameras? Enter the camera count, resolution, codec and frame rate, edit the bitrate if you have the camera’s own figure, then the recording mode and days to keep. The result gives the total Mbps into the recorder, a check against its maximum incoming bandwidth, the storage needed in TB and the drives that provides.
Starts at 1.8 Mbps for these settings. Change it to the figure on the camera.
On the recorder’s datasheet.
Total into the recorder
14.4 Mbps
1.8 Mbps per camera, 8 cameras
Recorder check
Within limit
65.6 Mbps spare of 80 Mbps
Storage needed
2.6 TB
9.7 GB per camera per day, 30 days, with 10% overhead
Drives needed
- 4 TB drives1
- 6 TB drives1
- 8 TB drives1
- 10 TB drives1
Check how many drive bays the recorder has before choosing a size.
Upload speed to watch remotely
4 Mbps
Every camera at once on its sub-stream. One camera full screen on its main stream needs 1.8 Mbps.
Recorders for 8 cameras
Formula
- Total Mbps = bitrate per camera × cameras. Compare it with the recorder’s maximum incoming bandwidth.
- GB per camera per day = Mbps ÷ 8 × 86,400 ÷ 1,000 × share of the day recorded.
- Storage (TB) = GB per camera per day × cameras × days ÷ 1,000 × 1.1. Decimal TB, as drives are sold.
- Drives = storage ÷ drive size, rounded up.
Bitrates assumed
| Resolution | H.264 | H.265 | H.265+ / smart codec |
|---|---|---|---|
| 2 MP (1080p) | 4.0 | 2.0 | 1.4 |
| 4 MP (1440p) | 6.0 | 3.0 | 2.1 |
| 5 MP | 8.0 | 4.0 | 2.8 |
| 8 MP (4K) | 12.0 | 6.0 | 4.2 |
Remote viewing uses each camera’s sub-stream: 1 Mbps on H.264 and 0.5 Mbps on H.265 or H.265+, per camera. Motion modes store 50% (busy scene) or 30% (quiet scene) of the day; the bandwidth into the recorder is not reduced.
Basis of the estimate
For each camera, the estimate starts from a representative bitrate for its resolution and codec at 25 frames per second, scaled to the frame rate you choose. H.265 needs approximately half the capacity that H.264 requires for equivalent quality, and motion-triggered recording typically retains 30–50% of continuous footage, according to how active the scene is. The bitrate is editable: if the camera datasheet gives a figure, use that.
Two checks follow. The cameras’ streams arrive at the recorder together, so the total in Mbps must stay under the recorder’s maximum incoming bandwidth, even when the cameras record on motion only. Storage is the bitrate converted to gigabytes per day, multiplied by the camera count and the retention period in days, plus 10% for the recorder’s own overhead, in decimal terabytes as drives are sold.
The figure is for planning purposes: actual bitrates vary with encoder settings, night mode and scene complexity. Always round up when specifying: choose the next drive size above the figure. Specify surveillance-rated drives (Seagate SkyHawk or WD Purple, for example); desktop disks are not suitable for recorders.
