Dahua Disk Storage Calculator
Estimate how much HDD capacity you need for your Dahua CCTV/NVR setup.
Bitrate is estimated from resolution, codec, FPS, and scene complexity.
How to use this Dahua disk calculator
If you are planning a Dahua NVR or XVR deployment, storage sizing is one of the most important steps. Underestimating disk requirements can cause old footage to be overwritten too early. Overestimating can raise project cost without adding practical value. This calculator helps you quickly estimate storage in TB using the same core factors installers use: camera count, bitrate, recording schedule, and retention days.
What the calculator includes
- Camera load: number of channels writing to disk.
- Compression impact: H.264 vs H.265 presets.
- Video intensity: FPS and scene complexity adjustments.
- Recording behavior: continuous recording or event-based percentage.
- Safety margin: overhead for metadata, variability, and real-world spikes.
Disk sizing formula used
The calculator uses a practical formula suitable for most Dahua surveillance projects:
Total TB = (Cameras × Bitrate Mbps × Recording % × Hours/day × 3600 × Days) ÷ 8 ÷ 1,000,000 × (1 + Overhead)
In plain terms, it converts total megabits written by all cameras into terabytes, then adds a buffer. This gives you a realistic planning number before you choose your HDD count and RAID strategy.
Dahua-specific factors that change storage
1) Smart Codec settings
Dahua Smart H.265+ can reduce storage significantly in scenes with low motion, but busy scenes may still consume high bitrate. For reliable planning, use measured bitrate from a live system whenever possible.
2) CBR vs VBR
Constant bitrate (CBR) makes storage more predictable. Variable bitrate (VBR) can save space in quiet conditions but spikes during motion. If your cameras are in traffic-heavy or retail areas, keep extra margin.
3) Main stream vs sub stream
Recording should usually happen on the main stream for forensic quality. Sub streams are better for remote viewing. If you record both streams, your storage needs can increase substantially.
4) Frame rate and shutter profile
Going from 15 FPS to 25 FPS often raises required bitrate and therefore disk usage. Higher detail targets (plates, fast movement) need more bitrate headroom.
Example: 16-camera 4MP Dahua setup
- 16 cameras
- 4MP, H.265, 15 FPS
- 24/7 recording
- 30-day retention
- 10% overhead
With typical bitrate assumptions, this frequently lands in the range where multiple surveillance-grade drives are required. The calculator helps you convert that estimate directly into approximate drive count.
Best practices before final purchase
- Run a 24-hour pilot and read actual bitrate from the NVR dashboard.
- Add at least 10-20% margin for busy scenes and seasonal changes.
- Use surveillance-class HDDs designed for 24/7 write workloads.
- Confirm Dahua recorder max capacity, bay count, and RAID support.
- Document expected retention policy per camera group (critical vs standard).
FAQ
Is this calculator accurate for every Dahua model?
It provides a strong estimate. Exact usage depends on camera model, encoding settings, motion profile, and firmware behavior. Treat the result as planning guidance and verify with real bitrate data.
Should I record on motion only?
Motion recording saves storage, but may miss context around incidents. Many installations use continuous recording in critical zones and motion/event schedules in low-risk areas.
How much overhead should I use?
10% is a common baseline. Use 15-25% if scenes are unpredictable, bitrate is VBR-heavy, or retention is a strict compliance requirement.
Use the calculator above, then validate with your real environment. That combination gives you the most reliable Dahua storage plan with fewer surprises after deployment.