How Many CCTV Cameras Does Your Business Need?

One of the most common questions we get asked is: "How many cameras do we need?" The honest answer is: it depends — but here's exactly what it depends on, and how to work it out.

Start With What You're Trying to Protect

Before counting cameras, define your objectives. CCTV systems can serve very different purposes:

• Deterrence — visible cameras that discourage theft or antisocial behaviour
• Evidence — capturing footage good enough for police or insurance use
• Operational monitoring — watching production lines, queue lengths or staff areas
• ANPR — recording vehicle registration plates at entry/exit points
• People counting / analytics — AI-based footfall and behaviour analysis

Each objective requires different camera types, positions and specifications. A deterrence camera near the entrance is very different from an evidential camera covering a cash desk.

Mapping Your Coverage Requirements

We start every CCTV project with a site survey and coverage map. Walk your site and identify:

• Entry and exit points — every door, gate, loading bay or vehicle access point
• High-value areas — server rooms, stock rooms, cash handling, safes
• Public-facing areas — reception, shop floor, car park
• Blind spots — corners, stairwells, areas that existing cameras miss
• External perimeter — boundary lines, external lighting, night-time conditions

Understanding Camera Coverage Angles

Camera field of view (FOV) is determined by the lens focal length. As a rough guide:

• 2.8mm lens — ~100° FOV, ideal for wide coverage in corridors and small rooms
• 4mm lens — ~80° FOV, good general purpose for most internal areas
• 6mm lens — ~55° FOV, better for longer distances and facial identification
• 12mm lens — ~25° FOV, telephoto for car parks and external distances
• Varifocal (2.8–12mm) — adjustable, most flexible for uncertain requirements

A 4mm lens camera mounted at 3m height will typically cover an area approximately 10–12m wide at 8m distance — suitable for a standard office or shop floor.

Camera Density by Area Type

As a general guide, here's how many cameras typical area types require:

• Small office (up to 200m²): 4–8 cameras (entrance, reception, key internal areas, external)
• Retail unit (200–500m²): 8–16 cameras (full floor coverage, cash desk, stockroom, external)
• Warehouse (1,000–5,000m²): 16–48 cameras (aisles, loading bays, perimeter, offices)
• Office building (multi-floor): 2–4 cameras per floor plus external and access points
• Car park (50 spaces): 6–12 cameras depending on layout and ANPR requirements

Don't Forget Storage and Retention

More cameras means more storage. A 4K camera recording continuously generates roughly 25–40GB per day. With 16 cameras and 30-day retention, you're looking at 12–19TB of raw storage — or significantly less with H.265 compression and motion-triggered recording.

We size NVR storage for your specific retention requirement (typically 30 or 90 days for UK commercial sites) accounting for your actual camera resolution and recording schedule.