CCTV and NVR storage calculator
Estimate the storage required for your CCTV footage
✓ This calculator is free to use - No credit card required
Common: 5 (low-light), 15 (standard), 30 (continuous), 40 (max)
H.265 provides ~50% better compression
Lower = better quality but larger file size
Results
Total Storage Required
2.20 TB
Estimated Cost
$110
Based on ~$50/TB NAS storage
Storage per camera per day
Calculated with the same model as the calculator, at 15 fps and a 2-second I-frame interval. Busy scenes use more, quiet scenes less.
| Resolution | H.264, per day | H.265, per day | H.265, 30 days |
|---|---|---|---|
| 2 MP | 20 GB | 10 GB | 302 GB |
| 4 MP | 40 GB | 20 GB | 603 GB |
| 8 MP | 80 GB | 40 GB | 1.2 TB |
How the calculation works
Storage is bitrate multiplied by time. A camera recording at 1 Mbps writes 10 GB a day: one megabit a second, 86,400 seconds a day, 8 bits to a byte. The calculator multiplies that by the number of cameras and the days of retention.
The automatic bitrate starts at about 2 Mbps per megapixel at 30 fps in H.264, then scales with the frame rate, the I-frame interval and the codec; H.265 roughly halves it. If you know the bitrate set in the camera, enter it: a real value beats any estimate.
Results are in the binary units an NVR uses for free space. A drive sold as 4 TB holds about 3.6 TB of these, so leave some margin. In RAID 5 one drive's capacity goes to parity, in RAID 6 two.
Hikvision, Dahua and other NVRs and DVRs
The arithmetic is the same for every recorder: what fills the disk is the bitrate of the cameras. Smart codecs such as Hikvision H.265+ and Dahua Smart H.265+ lower the average bitrate in scenes with little motion, so for those cameras enter the average bitrate the recorder reports.
A DVR records analogue HD cameras (HD-TVI, HDCVI, AHD) after encoding them in H.264 or H.265, so the same calculation applies to the bitrate it records at. In CCTVplanner, the design check compares the storage the placed cameras need with the recorders in the design.
Storage questions
How much storage do I need for CCTV?
Multiply each camera's bitrate by the seconds you keep footage and divide by 8. A 4 MP camera in H.265 at 15 fps records about 2 Mbps, roughly 20 GB a day or 603 GB for 30 days.
How big a hard drive does an NVR need?
Add up all the cameras for the retention you need and round up to the drive sizes the recorder takes. A drive sold as 4 TB shows about 3.6 TB in the recorder. If the total needs more than one drive, spread it over the recorder's bays or use RAID, which costs one drive's capacity in RAID 5 and two in RAID 6.
H.264 or H.265: which saves more storage?
H.265 needs roughly half the bitrate of H.264 for the same picture, so it roughly halves the storage. Most current IP cameras and NVRs support it.
Is there a Hikvision storage calculator?
Hikvision offers a Storage and Network Calculator in its HiTools Designer toolbox. This calculator gives the result for Hikvision cameras from the bitrate, frame rate, codec and retention, and works the same way for every other brand.
How long should CCTV footage be kept?
There is no single rule; many businesses keep about 30 days. Under the GDPR footage may be kept only as long as necessary: the European Data Protection Board says it should in most cases be deleted after a few days, and the longer the period, especially beyond 72 hours, the more it has to be justified.
Does the calculator work for a DVR?
Yes. A DVR encodes analogue HD cameras in H.264 or H.265 before recording them, so enter the bitrate the DVR records at and the same calculation applies.
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Plan your CCTV system with accurate storage calculations.