CCTV storage calculator
How long your CCTV keeps footage depends on four things: the number of cameras, their resolution, the compression (H.265 or H.264) and how many hours a day they record. Enter yours to see the days on each drive size, or the drive size for the days you want to keep.
To keep 30 days you need about
1.4 TB
A 2 TB surveillance drive is enough.
| Drive | Days (about) |
|---|---|
| 1 TB | 20 |
| 2 TB | 41 |
| 4 TB | 83 |
| 6 TB | 124 |
| 8 TB | 166 |
4 cameras at 1 Mbps for 24 hours a day record about 43.2 GB a day. An estimate: the real figure depends on the recorder, the scene and the settings.
How it is worked out
Each camera records at an average bitrate. Space per day = bitrate (Mbps) × 3,600 seconds × hours ÷ 8, in megabytes. A drive keeps about 90% of its labelled size for footage. The typical bitrates below are averages at about 15 frames a second; your recorder shows its own under the recording or video settings, and you can type it into the calculator.
| Resolution | H.265 | H.264 |
|---|---|---|
| 2MP (1080p) | 1 Mbps | 2 Mbps |
| 4MP | 2 Mbps | 4 Mbps |
| 5MP | 2.5 Mbps | 5 Mbps |
| 8MP (4K) | 4 Mbps | 8 Mbps |
Questions about recording space
How many days does a 1 TB drive record?
With 4 cameras at 2MP on H.265, recording all day, about 43 GB a day, so roughly 20 days on 1 TB. More cameras, higher resolution or H.264 shorten that; motion-only recording makes it longer.
Does H.265 really save space?
Yes. H.265 needs about half the space of H.264 for the same picture, so the same drive keeps about twice as many days. Most recent recorders support it; turn it on in the recording settings.
What happens when the drive is full?
Recorders overwrite the oldest footage automatically, so the drive always holds the most recent days. Copy anything important to a USB stick or your phone before it is overwritten.
Next step
Choose the recorder in the DVR and NVR guide, a ready-made CCTV kit (each wired kit names the drive size we recommend), or build your own in the System Builder. We deliver all products to every city in Pakistan. Installation, site visits and on-site service are available in Lahore only.