About this tool
Field of View / Angle of View Calculator is a free, in-browser tool that shows how wide a lens sees. Choose a sensor format (or enter custom sensor width and height), a focal length and a subject distance, and it returns the horizontal, vertical and diagonal angles of view plus the real-world width and height of the scene captured at that distance. All math is local and nothing is uploaded.
The angle of view along each axis is 2·arctan(dimension / (2·f)), where the dimension is the sensor width, height or diagonal and f is the focal length. The real-world coverage at a subject distance d follows from the geometry as d × sensor dimension / f, so a 50 mm lens on full frame (36 mm wide) at 3 m frames about 2.16 m across.
Use it to pick the right focal length for a shot: check how much of a room a wide lens covers, how tightly a telephoto frames a subject, or what sensor and lens combination matches a scene you have in mind.
Frequently asked questions
What is the difference between horizontal, vertical and diagonal angle of view?
Each uses a different sensor dimension in 2·arctan(dimension/(2·f)). Horizontal uses the sensor width, vertical the height, diagonal the corner-to-corner measurement — which is the largest and the figure lens makers usually quote.
How is the captured scene size calculated?
Coverage equals subject distance × sensor dimension ÷ focal length. Because it scales linearly with distance, doubling the distance doubles both the width and height of the framed scene.
Can I use a sensor that is not in the list?
Yes. Choose 'Custom' and type the sensor's width and height in millimetres — useful for medium format, cropped video modes, or unusual formats not covered by the presets.
Does this tool send my inputs anywhere?
No. The angles and coverage are computed entirely in your browser; your focal length, sensor and distance never leave your device.
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