Advanced CCTV Storage Calculator
Example Data Table
| Scenario |
Cameras |
Bitrate |
Recording |
Retention |
Activity |
Approx Storage |
| Small shop |
4 |
3 Mbps |
24 h/day |
14 days |
100% |
1.81 TB raw |
| Office motion mode |
8 |
4 Mbps |
24 h/day |
30 days |
45% |
4.67 TB raw |
| Warehouse |
16 |
5 Mbps |
24 h/day |
45 days |
100% |
38.88 TB raw |
Formula Used
The calculator uses a bitrate based storage formula. It first adjusts the video bitrate by codec profile and recording activity.
Effective video bitrate per camera:
Video Mbps × Codec Multiplier × Activity Factor
Effective audio bitrate per camera:
(Audio Kbps ÷ 1000) × Activity Factor
Total bitrate:
Cameras × (Effective Video Mbps + Effective Audio Mbps)
Daily storage:
Total Mbps × Recording Seconds Per Day ÷ 8 ÷ Storage Base
Total usable storage:
Raw Storage × (1 + Overhead %) × (1 + Reserve %)
Physical drive capacity:
Usable Storage ÷ RAID Usable Factor
How to Use This Calculator
- Enter the number of CCTV cameras in your system.
- Add the average bitrate for each camera.
- Enter audio bitrate if your cameras record sound.
- Choose recording hours and retention days.
- Use activity percent for motion based recording.
- Select the compression profile that matches your recorder.
- Add overhead and free space reserve for safer planning.
- Choose a RAID factor if your recorder uses redundancy.
- Press calculate and review usable and physical storage.
- Download the report as CSV or PDF.
CCTV Storage Planning Guide
Why Storage Calculation Matters
CCTV storage planning protects evidence, budgets, and system reliability. A recorder can only keep footage for the time allowed by its installed drives. If storage is too small, old footage is overwritten early. This can create problems during theft reviews, safety checks, insurance claims, and compliance audits.
Bitrate Is the Main Driver
Bitrate has the strongest effect on storage size. A camera recording at 8 Mbps needs about twice the space of a camera recording at 4 Mbps. Resolution, frame rate, compression, scene detail, and night noise all influence bitrate. For that reason, real systems should use measured recorder bitrate when possible.
Retention and Recording Style
Retention means how many days footage should remain available. A 30 day retention target needs twice the space of a 15 day target. Recording style also matters. Continuous recording uses storage all day. Motion recording uses less space, but only when activity is low. Busy entrances may still record most of the day.
Compression Changes the Estimate
Modern compression can reduce storage. H.265 often uses less space than H.264 at similar visual quality. Enhanced profiles may save more, but results vary. Highly detailed scenes, rain, trees, traffic, and low light noise can raise bitrate. Keep a reserve when planning important installations.
Overhead, RAID, and Reserve
Recorder databases, file systems, thumbnails, smart search data, and logs can consume extra space. RAID also changes usable capacity. Mirroring may cut usable storage in half. RAID 5 or RAID 6 protects against drive failure but still reduces available space. A free space reserve helps avoid running drives at their limit.
Better Buying Decisions
This calculator separates raw storage, usable storage, and physical drive capacity. That makes drive planning clearer. Use the physical capacity result when buying disks. Use the estimated days result to check whether your current recorder can meet the desired retention period.
Frequently Asked Questions
1. What is a CCTV storage calculator?
It estimates how much drive capacity a camera system needs. It uses camera count, bitrate, recording hours, retention days, compression, motion activity, overhead, and reserve.
2. Which value affects storage the most?
Bitrate usually has the largest impact. Higher bitrate creates more data every second. Camera count and retention days also scale the total storage directly.
3. Should I use Mbps or MBps?
Camera bitrates are usually listed in Mbps. This means megabits per second. The formula divides by 8 to convert bits into bytes for storage sizing.
4. Does motion recording save storage?
Yes, motion recording can save storage when scenes are quiet. Busy areas may still record often, so use a realistic activity percentage.
5. Why add overhead percentage?
Recorders use extra space for indexes, logs, thumbnails, file structure, and database records. Overhead helps create a safer storage estimate.
6. What does RAID usable factor mean?
It shows how much installed drive capacity remains usable after redundancy. RAID 1 often uses 50 percent. RAID 5 and RAID 6 depend on drive count.
7. Is H.265 always better than H.264?
H.265 often reduces storage at similar quality. Results depend on camera hardware, firmware, scene movement, lighting, and recorder settings.
8. Why keep free space reserve?
A reserve prevents planning too close to the drive limit. It helps handle bitrate spikes, extra cameras, longer retention, and recording overhead.