CCTV Storage Calculator
Work out how many terabytes your NVR or DVR needs. Enter your camera count, resolution, frame rate, codec and retention period — the result updates live.
System details
15 fps is standard for surveillance; 25–30 for high-motion areas.
30 days is the most common commercial requirement.
Storage required
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Get a Free Quote from AMT Systems →How CCTV storage is calculated
Storage is a direct function of bitrate over time: bitrate (Mbps) ÷ 8 × seconds recorded × days × cameras. The bitrate itself depends on resolution, frame rate, codec efficiency and how much compression you accept. This calculator uses typical real-world bitrates for surveillance scenes — a 4 MP camera at 15 fps in H.265 runs around 2–3 Mbps at medium quality.
Quick reference — continuous recording, H.265, 15 fps, 30 days, medium quality
| Cameras | 2 MP (1080p) | 4 MP | 8 MP (4K) |
|---|---|---|---|
| 4 | ~1.6 TB | ~3.1 TB | ~6.3 TB |
| 8 | ~3.1 TB | ~6.3 TB | ~12.5 TB |
| 16 | ~6.3 TB | ~12.5 TB | ~25 TB |
| 32 | ~12.5 TB | ~25 TB | ~50 TB |
Three ways to cut storage costs
- Use H.265 or a smart codec. Moving from H.264 to H.265 roughly halves storage; smart codecs (H.265+, Zipstream) save more on static scenes.
- Drop the frame rate. Surveillance rarely needs 30 fps. 12–15 fps is smooth enough for evidence in most scenes.
- Record motion where appropriate. A quiet warehouse aisle at 15% activity uses one-sixth the storage of continuous recording — but keep continuous recording on entrances, tills and other critical views.
Frequently asked questions
How much storage does a 4-camera system need?
With 4 MP cameras recording continuously in H.265 at 15 fps, plan on roughly 3 TB for 30 days. Motion-only recording can cut that by 50–80% depending on activity.
Does H.265 really halve storage vs H.264?
In practice H.265 reduces bitrate by 40–50% at comparable quality. Smart codec variants can push savings further on low-activity scenes.
Should I use surveillance-rated hard drives?
Yes — drives like WD Purple and Seagate SkyHawk are rated for 24/7 sequential writes from multiple streams. Desktop drives fail sooner under recording workloads.
How many days of footage should I keep?
30 days is the common commercial standard. Some industries and insurers require 60–90 days — verify your regulatory requirements before finalizing a design.
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AMT SYSTEMS LTD. designs and installs commercial CCTV across Toronto & the GTA — free site assessment included.
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