Advanced CCTV Disk Calculator
Formula Used
Video Mbps = Cameras × Bitrate per camera × Codec adjustment.
Audio Mbps = Cameras × Audio Kbps ÷ 1000.
Effective Mbps = (Video Mbps + Audio Mbps) × Duty cycle.
Daily GB = Effective Mbps × Recording hours × 3600 ÷ 8 ÷ 1000.
Retention GB = Daily GB × Retention days.
Recommended GB = Retention GB plus file overhead, RAID overhead, and safety margin.
This calculator uses decimal storage. One TB equals 1000 GB. TiB is also shown for closer operating system comparison.
How to Use This Calculator
Enter the camera count first. Add the average bitrate for each camera. Use the camera stream settings when possible.
Add audio bitrate if audio recording is enabled. Choose daily recording hours. Enter 24 for full-time recording.
Set retention days based on your policy. Use duty cycle for motion recording. Add overhead values for RAID, file indexing, and spare capacity.
Press calculate. The result appears above the form. Use the chart to compare raw and final storage. Export the result as CSV or PDF.
Example Data Table
| Setup | Cameras | Bitrate | Retention | Duty Cycle | Approx Daily Storage |
|---|---|---|---|---|---|
| Small shop | 8 | 3 Mbps | 14 days | 100% | 259 GB |
| Office | 16 | 4 Mbps | 30 days | 80% | 553 GB |
| Warehouse | 32 | 6 Mbps | 45 days | 60% | 1,244 GB |
| Campus | 64 | 5 Mbps | 60 days | 100% | 3,456 GB |
CCTV Disk Planning Guide
Why Storage Planning Matters
CCTV storage is often guessed too quickly. That can create real problems later. A system may record well at first. Then the disk fills early. Older video can disappear before the required retention period ends. This calculator helps you avoid that issue. It converts camera load into clear disk capacity.
Bitrate Is the Main Driver
Camera bitrate affects storage more than resolution alone. A 4 MP camera can use less space than a 2 MP camera. The difference comes from compression, frame rate, scene motion, and quality settings. Always check the actual stream bitrate. Use average bitrate for normal planning. Use maximum bitrate for safer planning.
Retention and Recording Style
Retention means how long video must stay available. More days need more space. Continuous recording uses the full daily load. Motion recording uses less space. The duty cycle field estimates that saving. A quiet office may record only part of the day. A busy street may record almost all day.
Overheads and Spare Capacity
Real systems need more than raw video space. Video recorders store indexes, logs, thumbnails, and metadata. RAID also changes capacity needs. Mirroring can double the physical storage requirement. Safety margin protects against bitrate spikes. It also helps when extra cameras are added later.
Using the Final Result
The recommended capacity is the main number. Compare it with available drive sizes. Round up, not down. Surveillance drives should not run completely full. Free space improves reliability and management. Use the export buttons for proposals, client reports, or internal records. Recalculate whenever camera settings change.
FAQs
1. What is CCTV disk storage?
It is the hard drive space needed to save camera footage. It depends on camera count, bitrate, recording hours, retention days, audio, compression, and overhead.
2. Which value affects storage the most?
Bitrate usually affects storage the most. Higher bitrate creates larger video files. Camera count and retention days also have a strong effect on total capacity.
3. Should I use Mbps or MBps?
Use Mbps for camera bitrate. CCTV stream settings usually show megabits per second. The calculator converts that value into gigabytes and terabytes automatically.
4. What does duty cycle mean?
Duty cycle is the active recording percentage. Use 100% for continuous recording. Use a lower value when motion detection records only part of the day.
5. Why add a safety margin?
A safety margin covers bitrate spikes, busier scenes, extra metadata, and future camera changes. It helps prevent early disk filling and lost retention.
6. Does RAID reduce usable capacity?
Yes. RAID can reserve capacity for parity or mirroring. Add the expected RAID overhead to estimate the physical disk space required for the setup.
7. Is H.265 always smaller than H.264?
Usually H.265 uses less space at similar quality. Actual savings depend on camera settings, scene movement, firmware, and the recorder configuration.
8. Why does my recorder show less space?
Operating systems and recorders may show binary capacity. They also reserve space for formatting, indexes, logs, and system files. This makes visible space lower.