Camera Spacing Calculator for Perimeter Coverage
Space cameras so their coverage cones overlap by about 15 percent, because a gap between two cones is a gap an intruder can walk through. A 2.8 mm lens covering a 20 foot deep strip spaces at roughly 31 feet.
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.
Gear that matches this answer
Chosen for this calculation.
REOLINK RLC-810A PoE Security Camera, 4K Wired Outdoor
$84.99The default 4K PoE bullet in this catalog: person and vehicle detection on the camera itself, so alerts are not triggered by every passing shadow.
- Resolution
- 8 MP
- Lens
- 4 mm
- Storage
- PoE, needs an NVR or NAS
Prices change often.
REOLINK PoE Security Camera RLC-810A 2 Pack, 4K, 100ft IR Night Vision
$194.99Two of the same camera, which is what most expansions actually need, at a lower price per unit than two singles.
- Resolution
- 8 MP
- Stated IR range
- 100 ft
Prices change often.
REOLINK RLC-1212A 12MP Bullet Outdoor PoE Camera
$129.99Twelve megapixels on a single camera, which buys real DORI identify distance on the one approach where you actually need a face rather than a shape.
- Resolution
- 12 MP
Prices change often.
Amcrest UltraHD 4K 8MP Outdoor Bullet Security IP PoE Camera, 98ft NightVision
$94.95Amcrest publishes its IR range and its lens focal length in the listing, which is rarer than it should be and is what makes a coverage calculation possible before you buy.
- Resolution
- 8 MP
- Stated IR range
- 98 ft
- Lens
- 2.8 mm
Prices change often.
Amcrest UltraHD 4K 8MP IP PoE AI Camera, 129 degree FOV, 49ft Color Nightvision
$109.99A 129 degree field of view covers a whole driveway from one mount, at the cost of pixel density: the wider the lens, the shorter the distance at which it can still identify anyone.
- Resolution
- 8 MP
- Field of view
- 129 degrees
- Stated IR range
- 49 ft
Prices change often.
Amcrest 5MP IP PoE AI Camera with 49ft Color Night Vision, Outdoor Bullet
$74.99Colour night vision rather than infrared monochrome, which preserves clothing and vehicle colour, the two details a police report actually asks for.
- Resolution
- 5 MP
- Stated IR range
- 49 ft
Prices change often.
The formula
effective width = coverage width x (1 - overlap), and cameras = perimeter / effective width
The overlap allowance is a convention rather than a standard. It exists because a person crossing the seam between two cameras should be in frame on at least one of them at all times.
Common questions
How far apart should security cameras be spaced along a perimeter?
Spacing depends on how wide each camera coverage cone is at the chosen depth, minus an overlap allowance. A 2.8 mm lens covering a 20 foot deep strip produces roughly 36.6 feet of coverage width, and after a 15 percent overlap allowance that works out to spacing cameras about every 31 feet along the perimeter.
Why leave overlap between adjacent camera coverage areas?
Overlap exists so a person crossing the seam between two coverage cones stays in frame on at least one camera at every moment, rather than passing through a gap where neither camera can see them. A 15 percent overlap allowance is a common convention, not a fixed standard, and a higher risk perimeter can reasonably use a larger allowance than that.
How many cameras does a 200 foot perimeter need?
Using a 2.8 mm lens covering a 20 foot deep strip with 15 percent overlap, each camera effective coverage width comes to about 31 feet, so a 200 foot perimeter divided by that effective width rounds up to 7 cameras total. A narrower lens or a shallower coverage depth increases that count, since each camera then covers less width.
Does a longer focal length lens need more or fewer cameras to cover the same perimeter?
More. A longer focal length narrows the field of view and therefore the coverage width each camera achieves at a given depth, so covering the same total perimeter takes more cameras spaced closer together. A wider lens like 2.8 mm covers more width per camera and needs fewer cameras overall, at the cost of less pixel density at distance.
What is coverage depth and why does it change camera spacing?
Coverage depth is how far out from the camera reliable coverage is needed, and scene width grows with distance, so a deeper coverage depth produces a wider coverage cone and allows wider spacing between cameras. A shallow 10 foot deep strip narrows the useful coverage width and forces cameras to sit closer together than a 20 foot deep strip would need.
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The camera count, storage and PoE budget worksheet, plus the wiring checklist, as one printable page.
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.