Dahua HDD Capacity Calculator
Estimate how much storage your Dahua camera system needs based on bitrate, retention, recording schedule, and redundancy.
What Is a Dahua Disk Calculator?
A Dahua disk calculator helps you estimate how much hard drive capacity is required for video surveillance recording. Instead of guessing, you enter practical values such as camera count, bitrate, retention days, and recording schedule. The calculator then gives you a realistic storage target in terabytes (TB).
This is especially useful when planning a new Dahua NVR deployment, expanding an existing CCTV system, or checking whether your current disk setup can handle longer retention requirements.
How Storage Is Actually Calculated
The core storage formula is straightforward:
After that baseline is computed, this calculator adds your selected safety overhead (for bitrate spikes, scene complexity, and recording variation). If RAID is selected, the tool also estimates the number of drives needed to achieve the required usable capacity.
Inputs That Matter Most
- Camera bitrate: Higher bitrate improves quality but increases disk usage.
- Retention days: More days means a larger total storage requirement.
- Recording schedule: 24/7 recording uses far more storage than motion-triggered recording.
- Compression codec: H.265 typically uses less storage than H.264 at similar quality.
- RAID mode: Redundancy reduces usable capacity, so more disks are required.
Typical Bitrate Guidance for Dahua Cameras
Use this as a quick planning reference before fine-tuning with real-world stream data:
| Camera Type | Codec | Typical Bitrate |
|---|---|---|
| 2MP (1080p) | H.265 | 2 to 3 Mbps |
| 4MP | H.265 | 3.5 to 5 Mbps |
| 8MP (4K) | H.265 | 6 to 10 Mbps |
| 2MP to 8MP | H.264 | ~30% to 70% higher than H.265 |
Example Planning Scenario
Suppose you have 16 cameras at 4 Mbps each, recording continuously for 30 days with a 10% overhead buffer. In most cases, this lands around the mid-20 TB range for usable storage. If you apply RAID 5 or RAID 6, you'll need additional raw disk space to account for parity.
Best Practices for Dahua Storage Sizing
- Use surveillance-grade HDDs designed for continuous write workloads.
- Leave headroom (typically 10% to 20%) for bitrate spikes and growth.
- Verify actual stream bitrates in your NVR after installation.
- Use motion recording only when your scene quality and event requirements allow it.
- Recalculate when adding cameras, increasing resolution, or extending retention policy.
FAQ
Is this calculator only for Dahua?
The math works for most CCTV systems, but it is especially useful for Dahua NVR planning because it follows the same bitrate-based sizing approach typically used in Dahua deployments.
Why does real storage differ from estimates?
Actual storage can vary based on scene motion, VBR behavior, frame rate, audio streams, and smart encoding settings. Treat results as planning estimates, then confirm with real recorded data.
Should I always choose RAID?
If uptime and fault tolerance are important, RAID is strongly recommended. Just remember: redundancy improves resilience but reduces usable storage capacity.