Interactive Calculator · 2026
CCTV Camera Storage Calculator
How big an NVR hard disk does your home CCTV need? Size it by cameras, resolution, bitrate, recording mode, and how many days of footage you want to keep — with a recommended surveillance HDD and an honest cost.
Total storage as retention grows
Storage scales linearly with retention days — the marker sits at your 30-day setting.
Your CCTV system
Modern, efficient — about half the storage of H.264 for the same quality.
Seeded from resolution + codec — override with your camera’s configured bitrate.
Storage & recommended HDD
Per camera
1.24 TB
Total storage
0.00 TB
Daily throughput
169 GB/day
Est. HDD cost
₹0
Recommended drive: 6 TB
Your footage needs 4.94 TB. We add ~15% headroom (for the file system, indexing and a safety buffer) and round up to the nearest common surveillance HDD. Buy a drive rated for 24×7 write (WD Purple, Seagate SkyHawk), not a desktop drive.
Total storage by resolution (H.265 / HEVC, 30 days)
At 4 cameras and 30 days of retention, your 4 MP system needs 4.94 TB.
Jumping to a higher resolution multiplies storage roughly in line with bitrate — 4 MP is about double 2 MP, and 8 MP roughly quadruple. Motion-only recording and H.265 are the two biggest levers for cutting it back.
| Resolution | Bitrate | Total storage | Recommended HDD |
|---|---|---|---|
| 2 MP 1080p Full HD | 2.0 Mbps | 2.47 TB | 4 TB |
| 4 MP 2K QHD | 4.0 Mbps | 4.94 TB | 6 TB |
| 8 MP 4K Ultra HD | 8.0 Mbps | 9.89 TB | 12 TB |
Real-world storage always varies
This is an estimate. Actual bitrate swings with scene complexity, motion, low-light infrared, and each camera’s encoder settings — a busy gate or street-facing camera can record far more than a quiet indoor one. Treat the result as a sizing guide, add headroom, and always fit a surveillance-grade HDD rated for continuous 24×7 writing rather than a standard desktop drive.
Download CCTV Storage Report PDF
System summary, recommended HDD, daily throughput, and per-resolution comparison.
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How the CCTV storage calculator works
This CCTV storage calculator sizes the NVR or DVR hard disk a home security system needs. Storage is driven by four things: the number of cameras, each camera’s bitrate (how many megabits per second it records), the recording mode (continuous 24×7 versus motion-only), and the retention — how many days of footage you want to keep before it overwrites.
The core formula is: storage (GB) = cameras × bitrate (Mbps) × duty factor × 86,400 s/day × retention days ÷ 8 ÷ 1024. We divide by 8 to convert megabits to megabytes and by 1024 to convert to gigabytes. Continuous recording uses a duty factor of 1.0; motion-only recording in a typical home averages around 0.4 (40% of the day). The calculator then rounds the total up to the nearest common surveillance HDD size — 1, 2, 4, 6, 8 TB and beyond — after adding about 15% headroom.
H.265 vs H.264 and bitrate
Codec choice roughly halves or doubles your storage. H.265 (HEVC) is the modern, efficient codec — a 4 MP camera streams around 4 Mbps. Older H.264 needs roughly 1.8× the bitrate for the same picture, so the same camera might need 7 Mbps. Selecting a resolution seeds a sensible default bitrate for the codec you pick, but you should override it with the actual bitrate configured on your cameras for the most accurate estimate.
How much CCTV storage do I need in India?
A common home setup — four 2 MP cameras on H.265, recording 24×7 for 30 days — needs roughly 2–3 TB, comfortably a single 4 TB drive. Push to 4 MP or 8 MP, add cameras, or extend retention and the requirement climbs fast. Always buy a surveillance-grade drive (WD Purple, Seagate SkyHawk) rated for continuous writing, and treat this figure as a planning estimate — real bitrate varies with motion, scene detail and night vision.
Related Guides — Deep-dive reading
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