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Field of View Calculator

Find scene width and pixel density at your target distance.

Free to use · Live results · Transparent formulas

A practical answer, with clear assumptions

Find the width of a flat scene perpendicular to the camera axis, then estimate horizontal pixels per metre. Use the manufacturer’s stated horizontal field of view for your exact lens and video mode.

How to use this calculator

  1. Enter the horizontal angle, rather than the diagonal angle.
  2. Measure the distance from the camera to the target plane along the optical axis.
  3. Enter the horizontal pixel count of the stream you will record.
  4. Check a real scene under the intended lighting and motion conditions.

The calculation

Scene width = 2 × distance × tan(horizontal FOV ÷ 2)
Horizontal pixels per metre = horizontal pixel count ÷ scene width

What the result includes

  • Angles are measured in degrees. The target plane is perpendicular to the optical axis.
  • This is a rectilinear, ideal-lens estimate and does not model fisheye lenses, optical distortion or edge stretching.
  • Pixel density describes sampling only. It does not guarantee a recognizable face or readable plate.
  • The full horizontal video resolution is used. Cropping, stabilization or a different stream may reduce useful pixels.

Common questions

How wide is a 90° view at 10 metres?

The ideal scene width is 20 metres. A 2,688-pixel stream gives 134.4 horizontal pixels per metre at that plane.

Can the coverage simulator use these values?

Yes. Open the simulator to place multiple cameras and visualize horizontal coverage. It uses the same scene-width geometry.

Keep planning

Visualize camera coverage, compare camera specifications or check recorder requirements.

Formulas are documented on this page and implemented directly. These planning estimates should be checked against actual system measurements. Sources & methodology →