Video Storage & CCTV NVR Drive Calculator
Calculate required CCTV NVR hard drive storage in Terabytes (TB), network ingest bandwidth, and drive bay configurations for security cameras.
Camera System Specifications
Network Bandwidth & Bitrate Ingest
Surveillance Hardware Best Practices
About this tool
How to use it
- Select a quick setup preset or enter your exact number of IP camera channels and resolution (1080p, 4MP 2K, 5MP, 4K UHD, or 12MP).
- Choose your compression codec (H.265+, standard H.265, H.264+, or standard H.264) and recording frame rate (15 FPS CCTV baseline).
- Specify your recording schedule duty cycle (24/7 continuous vs motion detection) and statutory retention requirement in days (e.g. 30 days).
- Select your RAID architecture (JBOD, RAID 1, RAID 5, RAID 6, or RAID 10) and drive size to determine total net storage needed, NVR bay count, and network ingest throughput in Mbps.
Why it matters
Underestimating CCTV hard drive requirements causes security video recorders to overwrite critical incident footage prematurely, while failing to check NVR incoming bandwidth ratings leads to dropped frames and video stuttering. This calculator models dynamic H.265+ smart compression, recording duty cycles, and RAID parity overhead to dimension the exact storage pool and NVR bay count you need.
When to use it
Use this tool when designing new IP security camera systems for commercial facilities or homes, upgrading older analog DVR systems to 4K IP NVRs, budgeting surveillance hard drive purchases (like Western Digital Purple or Seagate SkyHawk), or verifying compliance with legal 30-day or 90-day video archiving mandates.
Good to know
Calculations factor in real-world formatted drive capacities (1 TB HDD yields ~0.91 TiB of usable filesystem storage) and typical scene motion entropy. Always select surveillance-rated hard drives designed for 24/7 continuous write workloads and high-vibration multi-bay chassis.
Common questions
Why is 15 FPS recommended for security cameras instead of 30 FPS?
15 frames per second provides completely fluid, legally admissible motion capture for humans and vehicles while cutting video bitrates and hard drive storage consumption by almost 40% compared to 30 FPS.
How much storage does an 8-camera 4K system need for 30 days?
With standard H.265 compression at 15 FPS recording 24/7, an 8-camera 4K system requires approximately 18 TB of usable storage. Using modern H.265+ smart codecs reduces this requirement to approximately 11.5 TB.
What is the difference between regular desktop HDDs and surveillance HDDs?
Standard desktop hard drives are designed for 8 hours/day operation with 80% read and 20% write workloads. Surveillance-grade drives (such as WD Purple and Seagate SkyHawk) feature firmware optimized for 24/7 90% write streams, multi-drive rotational vibration sensors, and error recovery control to prevent dropped video frames.
What RAID level is best for a commercial NVR?
RAID 5 is the commercial standard for 4-bay to 8-bay NVRs, providing protection against any single drive failure with only one drive dedicated to parity. For 16-bay and enterprise systems, RAID 6 is recommended to protect against dual-drive failures during array rebuilds.
How does motion detection recording save hard drive space?
Motion detection only writes high-bitrate video streams when pixels in the frame change. In typical office, retail, or residential environments, motion occurs for 4 to 8 hours daily, reducing required storage capacity by 65% to 80% compared to 24/7 continuous recording.