How many security cameras do I need? Camera count calculator
Answer five questions about your doors, registers, back rooms, floor and lot to get the camera count, a numbered list of what each camera watches, and the recorder and switch that fit it.
Never counted: restrooms, locker rooms, changing rooms and fitting rooms do not get a camera.
Assumptions spare room and multi-sensor cameras, typical values
Typical: 2. The guide: pick the size that fits with a channel or two left over.
A multi-sensor camera uses one recorder channel or license per sensor on many systems.
Typical: 2 to 4 lenses in one housing.
Recorder sizes are the common 4, 8, 16 and 32 channel models, with 64 for larger sites; switch sizes are the common 4, 8, 16, 24 and 48 PoE port models.
8-channel recorder, 2 channels left for later. Covers the 2 spares you set.
6 PoE ports for cameras, plus one for the uplink. An 8-port switch fits them with 2 spares (typical sizes 4, 8, 16, 24 and 48).
An estimate from the inputs above; a site survey sets the real numbers.
The camera list
- 1Front door, faces coming inInside, facing the door, 8 to 12 ft away and low. Identify.Check its distance
- 2Rear door, faces coming inInside, facing the door, 8 to 12 ft away and low. Identify.Check its distance
- 3Register 1, from aboveAbove and slightly in front, on the drawer, counter and hands.Check its distance
- 4Stock roomIn a corner, seeing the door and the shelves at once.Check its distance
- 5Office or cash roomIn a corner, seeing the door and the safe or desk.Check its distance
- 6Floor overviewWide, from a corner: what happened, not who. Observe.Check its distance
How to use the camera count calculator
- Start from an example, or from zero. Tap the example closest to your business, then change the numbers to match your own space.
- Walk the space in your head, door by door. Count each door people use to come in, each register, each back room worth protecting, each open area and aisle, and each lot.
- Read the count and the list. The big number is the camera count; the list says what each camera watches and where it goes.
- Check the system. The recorder and switch sizes follow from the count, with the spare room you set.
- Check each camera. Use the distance calculator from any line of the list to size its lens.
How many cameras: one for each question
Square footage does not set the number. Every camera should exist to answer a question someone will ask after something goes wrong, so the calculator applies the five rules from our guide to how many cameras a business needs, in the order an installer walks a space.
Cameras = doors + registers + back rooms + overviews + outside cameras
Overviews = open areas + 2 × split areas + aisles
Recorder = the smallest of 4, 8, 16 or 32 channels that fits the channels used, plus spares
Switch = one PoE port per camera, plus one for the uplink
A door gets its own face camera because identifying a face takes 250 pixels per meter, about 76 per foot, under IEC 62676-4, so a 4MP camera can identify across a strip only about 34 ft wide whatever its lens. One wide camera can watch an open room, but it cannot identify faces at two doors far apart or see behind shelving. Restrooms, locker rooms, changing rooms and fitting rooms never get a camera; New York Labor Law 203-c and General Business Law 395-b cover them. This is general information, not legal advice.
Worked example: a small shop
The Small shop example has a front and a rear door, one register, a stock room, an office and one open sales floor.
- Two doors people use: 2 face cameras, one inside each door.
- One register: 1 camera above it, on the drawer and the hands.
- A stock room and an office: 2 cameras, one in a corner of each.
- One open floor: 1 wide overview. 2 + 1 + 2 + 1 + 0 = 6 cameras.
- Six cameras fit an 8-channel recorder with two channels left for later, and take 6 PoE ports plus one for the uplink.
How many cameras for a cafe, shop, office or warehouse
| Business | Doors | Registers | Back rooms | Overviews | Outside | Cameras |
|---|---|---|---|---|---|---|
| Small cafe | 2 | 1 | 1 | 1 | 0 | 5 |
| Small shop | 2 | 1 | 2 | 1 | 0 | 6 |
| Shop with three aisles | 2 | 2 | 1 | 3 | 0 | 8 |
| Office suite | 2 | 0 | 1 | 1 | 0 | 4 |
| Repair shop with a lot | 3 | 1 | 1 | 1 | 2 | 8 |
| Small warehouse | 3 | 0 | 1 | 4 | 2 | 10 |
Worked examples, not quotes: a different floor plan changes the count, and the walk through decides it.
Common mistakes when counting cameras
- Counting by square feet. A 1,500 sq ft open room can be watched by one wide camera; the same room with tall shelving needs three.
- Buying the four camera box first. It leaves a rear door or a stock room with no answer.
- One wide camera for two doors. It records both doorways but identifies neither, and sees each door from the side.
- Several cameras on the same floor. Each one still uses a channel, a port, storage and a cable run, and answers nothing new.
- Filling the recorder on day one. Adding a camera to a full recorder means replacing the recorder.
Camera count questions
How many security cameras does a small business need?
Count one camera per question: a face camera at each door people use, one above each register, one in each stock room or office worth protecting, one overview per open area, and one or two outside if there is a lot. A small shop with front and rear doors, one register, a stock room and an office needs 6 cameras. A cafe with one register and a storage room needs 5.
How many square feet does one security camera cover?
There is no fixed number, because walls and shelving decide coverage, not area. In an open room, one wide 4MP camera in a corner can observe a 42 by 36 ft floor, about 1,500 sq ft. Add two rows of tall shelving to the same room and that camera sees about half of it.
Do I need a camera at every door?
At every door people use to come in, yes, because the door is where the camera gets a face. An emergency exit that stays closed and alarmed can be left to an overview camera. A pair of doors side by side counts as one opening and one camera.
How many cameras can one NVR handle?
Recorders are commonly sold with 4, 8, 16 or 32 channels, one per camera stream, and the recorder's bandwidth and drive space set limits too. Pick the size that fits your count with a channel or two left over. A multi-sensor camera often uses one channel per sensor.
Can I add more security cameras later?
Yes, if the system has room: spare recorder channels, spare switch ports and power, drive space for the added video, and a path for one more cable. Planning one or two spares now makes a later camera a cable and a mount instead of a new recorder.
Sources and standards
- IEC 62676-4:2014Video surveillance systems for use in security applications, Part 4: Application guidelines. Identify 250 px/m (76.2 px/ft), the density behind one face camera per door.
- NY Labor Law, section 203-cNo employer video recording of employees in restrooms, locker rooms or rooms designated for changing clothes, unless a court order authorizes it.
- NY General Business Law, section 395-bViewing and video recording devices in fitting rooms, restrooms, toilets, bathrooms, washrooms, showers and hotel rooms.
- Recorder and switch specification sheetsCommon recorder channel counts (4, 8, 16, 32) and PoE switch port counts, typical values from makers' published specifications.
Want the count for your own space?
We walk the building, then send a written scope. Same-day quotes when we can. Licensed and insured.