Home / Camera Field of View Calculator
By Ali Zafar
Camera Field of View Calculator
Work out a camera's horizontal field of view, the scene width at a given distance, and whether the resulting pixel density is enough to identify a face or read a plate — using the pixel-density levels defined in IEC 62676-4 (Detection, Observation, Recognition, Identification), as published by Axis.
Camera & lens
Field of view
How this calculator works
Focal length and sensor size alone only tell you the angle of view — they don't tell you whether the camera is actually useful at the distance you're placing it. A wide lens covering a whole parking lot is worthless for identification if every face is compressed into a handful of pixels. That's why this calculator carries the field of view all the way through to pixel density at your chosen distance, not just the angle.
Worked example
1/3" sensor (4.8mm × 3.6mm), 4mm focal length, 5MP camera (2592px horizontal resolution), subject at 15m.
| Step | Result |
|---|---|
| Horizontal field of view (HFOV) | 2 × atan(4.8mm ÷ (2 × 4mm)) = 2 × atan(0.6) = 61.9° |
| Scene width at 15m | 2 × 15m × tan(61.9° ÷ 2) = 2 × 15m × 0.6 = 18 m |
| Pixel density | 2592px ÷ 18m = 144 px/m |
| Classification | 125 px/m ≤ 144 px/m < 250 px/m → Recognition-grade |
| Max recognition distance (125 px/m) | 2592px ÷ (2 × 125 × 0.6) = 17.3 m |
| Max identification distance (250 px/m) | 2592px ÷ (2 × 250 × 0.6) = 8.6 m |
At 15m this setup is recognition-grade — enough to recognize a familiar person or vehicle, but short of the 250 px/m needed to identify someone. To reach identification-grade, the subject would need to be within about 8.6m of the camera; past about 17.3m the pixel density also drops below the 125 px/m recognition threshold, even though the lens still "covers" that distance.
DORI levels: what the pixel density actually means
The DORI levels (Detection, Observation, Recognition, Identification) come from IEC 62676-4 and are published by manufacturers such as Axis to translate a raw pixel-density number into a real-world capability. They define four practical thresholds:
| Classification | Pixel density | What it means in practice |
|---|---|---|
| Identification | ≥ 250 px/m | Enough detail to confirm who a person is, or read a plate |
| Recognition | ≥ 125 px/m | Enough to recognize a familiar face or vehicle type |
| Observation | ≥ 63 px/m | Enough to follow what a person is doing and notice general details, not enough to recognize or identify them |
| Detection | ≥ 25 px/m | Enough to notice that a person or vehicle is present |
Below 25 px/m, footage is generally only good for general scene monitoring — not for picking out detail after the fact. These thresholds are why a camera spec sheet's megapixel count means very little on its own: the same sensor and lens gives identification-grade detail at the doorway and barely detection-grade detail at the far end of a parking lot.
Real-world caveats
This calculator gives the geometric ideal — it doesn't account for lens distortion (especially at the edges of wide-angle lenses), video compression artifacts, low light or backlight conditions, or a subject that isn't facing the camera. Treat the pixel-density numbers as a best-case ceiling, and add margin for anything mission-critical like a license-plate-capture point or a controlled entry.
Frequently asked questions
Which sensor size should I pick if I don't know mine?
Check the camera's datasheet — it's usually listed as a fraction like 1/2.8" or 1/3". If you genuinely can't find it, 1/2.8" is the most common sensor size in current IP cameras and a reasonable default.
Why does my camera's real-world coverage look narrower than the result here?
This calculator gives the geometric ideal. Lens distortion, especially toward the edges of a wide-angle lens, and the camera's actual mounting angle both reduce usable coverage compared to the raw math. Treat the number as a best-case reference, not an exact match to what you'll see on screen.
What pixel density do I actually need for identifiable footage?
Under the IEC 62676-4 (DORI) levels, identification needs about 250 pixels per meter or more at any point where you need to identify a face or read a plate. Recognition (125 px/m), observation (63 px/m) and detection (25 px/m) are fine for general monitoring but usually aren't detailed enough to confirm identity.
Related CCTV tools
With coverage confirmed, check the network next: the IP Camera Bandwidth Calculator sizes the total bitrate and uplink, and either the NVR Storage Calculator or the CCTV Storage Calculator (for mixed analog/IP jobs) works out drive space for the retention period you need.
Related tools & guides
Not sure how to pick the lens in the first place, or why a wider field of view can leave everyone in it unidentifiable? See Choosing the Right CCTV Lens: Coverage vs. Identification Distance.
See also IP Camera Bandwidth: Why the Switch (and PoE Budget) Fail Before the Network Does for the two mistakes that break installs even when bandwidth looks fine.
Sources
- Axis Communications white paper, "Pixel density based on IEC 62676-4:2014" (April 2026)
- Axis Communications white paper, "Pixel density" (May 2022; this link opens the PDF)
The Detection, Observation, Recognition and Identification levels (25, 63, 125 and 250 px/m) are as published by Axis in the papers above. IEC 62676-4 itself is a paid standard and its text was not used here. Axis notes that an IEC 62676-4:2025 edition exists; the levels on this page are the 2014-based ones from the Axis papers.