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HomeSecurityCalc

How Many Security Cameras Do I Need?

Industry convention The entry-point convention, not a standard
Quick answer

Count one camera per exterior door, one wide camera per three reachable ground floor windows, and one on the driveway. A typical three bedroom home with three exterior doors lands on six to eight cameras, which is an eight channel recorder.

Exterior cameras
7.00
Interior cameras
1.00
Total cameras
8.00
Recorder size
8.00 channels

Values update as you change the inputs. Where a figure cannot be computed honestly from what manufacturers publish, this calculator says so rather than showing a zero.

Systems sized for this camera count

This grid re-orders itself against the number you just calculated, smallest adequate option first.

The formula

cameras = exterior doors + (reachable ground floor windows / 3) + driveway + (floor area / 1,500 interior)

This is an industry convention rather than a published standard. It is built on entry points because that is what gets used, and floor area only adds interior coverage.

Common questions

How many security cameras does a 2,000 square foot house need?

With three exterior doors, eight reachable ground floor windows, and a driveway, the entry point convention adds up to about seven or eight cameras: one per door, one wide camera per three windows, one on the drive, plus roughly one interior camera for the floor area. That total points to an eight channel recorder rather than a smaller four channel box.

Do second floor windows count toward how many cameras a house needs?

No. This convention only counts reachable ground floor windows, since those are the ones a person can climb through without a ladder. Upper floor windows are left out of the exterior camera count entirely, even on a two story home. Floor area, not window height, is what adds a small amount of interior coverage instead.

Is camera count based on square footage or on doors and windows?

Doors and windows, not square footage. This calculator uses an entry point convention rather than a standard, because burglars use doors and reachable windows, not floor area. Square footage only adds a rough interior coverage figure on top of that exterior count, roughly one interior camera for every 1,500 square feet, so a bigger house with the same three doors does not need more exterior cameras.

How many cameras does a driveway or garage need?

This convention adds exactly one camera for a driveway or garage, regardless of how long the driveway is, on the assumption that one wide angle camera captures approaching vehicles and foot traffic from the street. If the driveway is unusually long or curved, a second camera aimed the other direction covers ground the first one cannot see, though the calculator itself only ever adds one by default.

What size NVR or recorder do I need for 7 or 8 cameras?

Recorders are sold in fixed channel counts, typically 4, 8, 16 and 32, and the practical choice is the next size up from your camera count. Seven or eight cameras, the result for a typical three door home, calls for an eight channel recorder rather than a four channel box, since a four channel unit leaves no room to add a camera later.

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Keep going

A calculated figure is a planning number, not a promise. Every answer here comes from published standards and manufacturer specifications, and real installations vary with light, weather, scene motion and how a camera is actually aimed. Where a figure cannot be computed honestly from what manufacturers publish, this calculator says so rather than showing a zero.

Before you point a camera at anything. Aim at your own property and your own boundary, never into a neighbour's windows. Cameras in bedrooms, bathrooms or anywhere with a reasonable expectation of privacy are a serious legal problem, including for guests and anyone who works in your home. Audio is legally different from video, many US states require the consent of every party to a recorded conversation, and several recorders capture audio by default, so check your own state before enabling it. This is researched general information and not legal advice.