NVR Storage & 4K Security Camera Bitrate Calculator

Enter your IP camera count, resolution, video codec (H.265 vs H.264), and desired footage retention days to calculate required hard drive terabytes, daily data, and network bandwidth.

How Security Camera Bitrate Converts to NVR Storage

Calculating surveillance video storage requires converting video transmission bitrates (measured in Megabits per second, Mbps) into formatted hard drive capacity (Terabytes, TB). The formula is:

Storage (GB) = [Bitrate (Mbps) × 3,600 seconds × 24 hours × Days] ÷ 8 bits per Byte ÷ 1,024 MB per GB

For example, a single 4K camera using standard H.265 at 8 Mbps generates 84.4 GB per day, consuming 2.53 TB over 30 days. By contrast, an older H.264 camera demands 16 Mbps, generating over 5.06 TB for the exact same 30-day window. Enabling H.265+ Smart Codecs drops static night scene bitrates dramatically, allowing four 4K cameras to fit easily onto a single 6TB to 8TB surveillance drive.

Surveillance Hard Drive Selection: WD Purple vs Seagate SkyHawk

Never install desktop hard drives (such as WD Blue or Seagate BarraCuda) in an NVR. Desktop drives are rated for only 8 hours of light desktop usage (80% read / 20% write). NVRs perform 95% continuous sequential writes 24 hours a day, 365 days a year. Always install dedicated surveillance drives:

• Western Digital Purple / Purple Pro: Features AllFrame firmware that prioritizes continuous write streams over error recovery checks, preventing dropped video frames.
• Seagate SkyHawk / SkyHawk AI: Features ImagePerfect firmware and built-in Rotational Vibration (RV) sensors designed to mitigate chassis vibration in multi-bay NVRs.