Horizontal field-of-view estimator
Use the exact camera’s published horizontal angle to estimate scene width at a known distance.
Approximation for a rectilinear view facing a flat target plane squarely. Distance is along the viewing axis to that plane, not a sloping ground or edge distance. Fisheye, panoramic/dewarped views, tilt and lens distortion need model-specific checks.
Formula, limits and technical sources
Width = 2 × distance × tan(horizontal angle ÷ 2). Required angle = 2 × atan(width ÷ (2 × distance)), converted to degrees. Average pixel density = image width in pixels ÷ scene width.
Distance and target width use the same selected unit. Outputs are m and px/m, or ft and px/ft. Switching units converts lengths. Tool input limits: 0.01–10,000 length units, 0.1–170° and 1–100,000 whole pixels. These are tool limits, not camera specifications; views close to 180° are excluded.
The approximation follows Edmund Optics’ geometry, Equation 2. Axis explains lens/sensor combinations and image-quality limits; its pixel-density discussion relates image resolution to scene width.
Pixel density is a spatial average, not a guarantee of face identification or useful recorded detail. Check focus, motion, lighting and compression. This tool does not select a focal length, camera or sensor.
Request a lens configurationInclude distance, required width, image width, mounting height and your day/night viewing task.