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Cameras

NVR storage calculator

Estimate how much drive space your cameras need by bitrate, codec, recording mode, and retention, and see how much H.265 and motion-only recording save.

Use this before buying surveillance drives to size storage for N cameras at a given resolution/codec and retention window — and to see how much H.265 and motion-only recording save.

Low priority

Plan for about 5.7 TB of recording storage

4 cameras at ~4.0 Mbps each, recording continuously, retained 30 days — roughly 5.7 TB including ~10% headroom. Treat this as a VBR estimate, not an exact figure.

Storage needed
5.7 TB

Includes ~10% overhead; size the drive at or above this.

Per camera / day
43.2 GB

~4.0 Mbps main stream

All cameras / day
172.8 GB
Retention
30 days

First checks

  • Assumed ~4.0 Mbps per camera (4MP H265 at standard fps).
  • Recording mode: continuous (24/7).
  • Confirm the real main-stream bitrate in the camera's own web UI for the most accurate number.

Step-by-step troubleshooting

  1. 1

    Read the camera's actual bitrate

    In the camera's web UI, note the configured main-stream bitrate (Mbps) and codec.

    Expected: You have a real per-camera bitrate instead of an estimate.

    Next: Enter it in the bitrate override field and re-run for an accurate figure.

  2. 2

    Choose recording mode + retention

    Decide continuous vs motion-only and your retention window; both scale storage linearly.

    Expected: The storage figure matches the policy you actually want.

    Next: Size the drive at or above the result, with CMR surveillance drives.

What your answers suggest

  • Formula: bitrate (Mbps) × 10.8 = GB/day per camera; × cameras × retention × 1.1 headroom.
  • 4 × 43.2 GB/day × 30 days ≈ 5.2 TB (before headroom).

Likely cause area

  • H.265 / H.265+ stores roughly half of H.264 for the same scene — switching codec is the biggest single lever.
  • Frigate records the main stream as-is (passthrough), so storage ≈ the camera's main-stream bitrate × time.

Safe actions

  • Pick a CMR surveillance-rated drive at or above 5.7 TB; never plan to fill it past ~80%.
  • If the number is too high: switch to H.265/H.265+, lower fps, or use motion-only recording.
  • For multiple drives, size for the total and keep headroom for the recordings index.

When to stop

  • Don't size to exactly 100% of the drive — surveillance drives should keep free space for overwrite/index.

Assumptions

  • Bitrates are VBR estimates — busy scenes spike above the average, static scenes fall below.
  • H.265 ≈ half H.264 is scene-dependent, not a hard guarantee.
  • Frame-rate effect is approximate and increases with fps.

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What should I check first?

  • Read each camera's actual main-stream bitrate (Mbps) and codec from its own web UI.
  • Decide continuous vs motion-only recording and your retention window — both scale storage linearly.
  • Confirm the drive is CMR surveillance-rated and you won't fill it past ~80%.

What is likely wrong?

  • Sizing on H.264 when the camera can do H.265/H.265+ (roughly half the storage).
  • Assuming the vendor's 'max bitrate' is the real usage — VBR averages are lower but spike on busy scenes.
  • Forgetting recordings-index overhead and planning to fill the drive to 100%.

What is safe to try?

  • Switch codec to H.265/H.265+ or lower fps to cut storage before buying bigger drives.
  • Use motion-only recording for low-activity cameras to extend retention.
  • Round up to the next standard drive size and keep ~10-20% free.

When should I stop?

  • Stop before buying if you haven't confirmed the camera's real bitrate — estimates can be off by 2x.
  • Stop before relying on a single drive for irreplaceable footage; recording storage is not a backup.

Source-backed checks

HomeTechOps turns official docs and conservative safety rules into a shorter runbook. These links are the source trail for the page direction.

Frigate docs: Recommended hardwareUsed for detector inference times, the cameras ≈ (1000 ÷ inference_ms) ÷ detect_fps capacity model, and the current 'Coral no longer recommended for new installs' guidance.Frigate docs: Camera setup (detect vs record streams)Used for the detect-on-substream / record-on-main pattern that drives bandwidth and detector load.FS.com: Understanding PoE standards and wattageUsed for the 802.3af/at/bt source-vs-delivered power figures and the switch total-PoE-budget constraint.