If you are sizing a CCTV installation, the most common mistake is underestimating storage and bandwidth. This Dahua calculator helps you quickly estimate how much disk capacity you need for your NVR or server based on camera count, bitrate, schedule, and retention period.
Dahua Storage & Bandwidth Calculator
What this Dahua calculator does
This tool estimates two critical things:
- Total incoming bandwidth for your recorder/network.
- Total storage required for the number of days you want to keep video.
It is designed for practical planning during camera system design, upgrades, or hardware procurement. While it is not an official manufacturer calculator, it follows the same core logic used by professional CCTV sizing workflows.
How the math works
The calculator uses this process:
- Multiply camera count by average camera bitrate to get total stream bitrate.
- Convert bitrate to daily data volume based on recording hours and recording activity percentage.
- Multiply daily volume by retention days.
- Add a safety margin to cover metadata, variable bitrate spikes, and real-world overhead.
In simplified form: Storage = cameras × bitrate × time × retention × margin.
How to choose realistic bitrate values
Bitrate depends on more than resolution
Many people assume all 4MP cameras use the same space. In reality, bitrate changes based on scene complexity, frame rate, codec, quality settings, and noise levels at night.
Practical starting points
- 2MP H.265: usually 1.5 to 3 Mbps
- 4MP H.265: usually 3 to 6 Mbps
- 8MP H.265: usually 6 to 12 Mbps
- H.264 streams often require noticeably more storage than H.265
If you have access to your current NVR, check real stream statistics and use those values for the most accurate estimate.
Deployment tips for Dahua systems
1) Plan for peak traffic, not average traffic
Scene movement, weather, and lighting can temporarily increase bitrate. Keep headroom in your network and recorder throughput.
2) Use a safety margin
A margin of 10% to 20% is a common planning range. Larger projects or critical sites may need more conservative buffer.
3) Consider recording mode carefully
Continuous recording gives full evidence coverage but requires much more storage. Motion/event recording can reduce usage significantly, but only if analytics and sensitivity are configured correctly.
4) Think in usable capacity
Raw disk size is not the same as usable retention in live operations. RAID behavior, file system overhead, and spare capacity targets all matter.
Example scenario
Suppose you have 32 cameras at 4 Mbps each, recording 24 hours/day for 30 days with a 15% margin. Your rough storage requirement is around 47 TB. That usually means planning a multi-drive layout rather than a single large disk.
Frequently asked questions
Does this replace official Dahua design tools?
No. This calculator is an independent planning aid. For procurement-grade designs, always verify with official product documentation and model-specific limits.
Should I always use H.265?
In most modern deployments, H.265 reduces storage significantly. However, compatibility, decoding load, and policy requirements may still lead some sites to choose H.264.
How accurate is this estimate?
It is usually good for early sizing and budgetary planning. Final numbers should be validated with real camera settings and sample recordings from your exact scene conditions.
Final takeaway
A solid Dahua calculator workflow prevents expensive mistakes: dropped retention, overloaded recorders, and emergency storage upgrades. Use this tool to create a baseline, then fine-tune with live bitrate data before final hardware decisions.