Cameras
NVR storage calculator
Estimate how much drive space your cameras need by bitrate, codec, recording mode, and retention.
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.
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
- Per camera / day
- 43.2 GB
- All cameras / day
- 172.8 GB
- Retention
- 30 days
Includes ~10% overhead; size the drive at or above this.
~4.0 Mbps main stream
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
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
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.
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.