How Many Security Cameras Do I Actually Need?

Most people arrive at a number the same way: they walk around the building, count the walls, and buy a camera for each one. That's how you end up with eight cameras watching empty siding and nothing usable of the person who actually walked up your driveway.

A better way to count is to stop thinking about walls and start thinking about choke points.

Start with the ways in

Almost everyone who comes onto a property arrives through a small number of predictable places: a driveway, a front door, a back gate, a side path, a loading door. Those are your choke points, and covering them well beats covering everything badly.

Walk the property and write down every route someone could take from the street to a door. For a typical suburban house that's usually three or four: the driveway, the front entry, and one or two side or rear approaches. For a small business it's the customer entrance, the staff or delivery door, and wherever the till or safe lives.

Decide what each camera is for

This is the distinction that changes your count more than anything else. Every camera is doing one of two jobs:

• Overview — showing what happened. A wide view of the driveway that tells you a vehicle pulled in at 2:14am and someone got out.
• Identification — showing who. A tighter view at a doorway or gate where a face or a plate fills enough of the frame to actually be recognisable.

A wide camera mounted high, covering your whole front yard, will reliably tell you that something happened and almost never tell you who. That's the single most common disappointment with a self-designed system. You generally want at least one identification camera at your main entry point, positioned close and at head height, and overview cameras doing the broader work.

Rough starting points

These aren't rules, but they're where most properties land:

• Average house: 4 cameras — driveway, front door, back door, and one covering the rear or a blind side.
• Larger house or corner lot: 6–8, adding side approaches and any detached garage or workshop.
• Small shop or office: 4–6 — customer entrance, back door, till or reception, stockroom.
• Warehouse or yard: 8–16, driven by gates, loading bays, and how much open ground needs watching.

Your recorder decides your ceiling

Recorders come in fixed channel counts — typically 4, 8, 16, 32, or 64 — and one channel means one camera. It's worth buying one size up from what you need today. Going from four cameras to five on a 4-channel recorder means replacing the recorder; on an 8-channel it means buying a camera. The price difference between a 4- and an 8-channel recorder is usually much smaller than the cost of that mistake.

The mistakes that cost the most

• Mounting too high. A camera at roof height gets you the top of a head. Seven to nine feet is high enough to be out of reach and low enough to catch a face.
• Covering ground instead of routes. A camera pointed at the middle of a yard watches grass. Pointed at the gate, it watches everyone who uses the gate.
• Forgetting the recorder. If someone can walk out with the box holding all your footage, the cameras were decoration. Put it somewhere out of the way, and consider a camera covering the room it's in.
• Buying for the whole property at once. Cover your main routes properly first. Adding cameras later is easy if you sized the recorder with room to spare.

If you'd rather not guess

Working this out from a description is genuinely quick for someone who does it often. Tell us the property, what you want covered, and any specific worry — a dark side alley, a long driveway, a gate 200 feet from the house — and we'll tell you what it takes. If that's fewer cameras than you were planning to buy, we'll say so.