Field of View Angle Calculator
Work out the horizontal, vertical and diagonal angle of view for any lens and sensor — and how wide a scene it covers at a given distance.
How it works
Angle of view = 2 × arctan(sensor dimension ÷ (2 × focal length)) · Scene width = 2 × distance × tan(AOV ÷ 2)
The angle of view is a piece of trigonometry: the sensor dimension is the far side of a triangle whose apex sits at the lens, so the half-angle is the arctangent of half the sensor size over the focal length. Because a sensor has three dimensions — width, height and diagonal — a lens has three angles of view, and the diagonal figure is the one usually quoted in lens specs. Multiplying by the subject distance turns the angle into a real-world width, telling you how much of a scene will actually fit in the frame.
Worked example
A 35 mm lens on a 36 × 24 mm full-frame sensor gives a horizontal angle of 2 × arctan(36 ÷ 70) = 54.4°. At 3 m that covers 2 × 3 × tan(27.2°) = 3.09 m across.
Sources: Angle of view (Wikipedia)
Frequently asked questions
Why is the diagonal angle of view largest?
The diagonal is the longest sensor dimension, so it subtends the widest angle. Lens marketing usually quotes the diagonal angle because it is the biggest and most impressive of the three figures.
Does this account for crop sensors?
Yes — the sensor you pick sets the physical width and height used in the formula, so a smaller sensor automatically returns a narrower angle of view for the same focal length.
Is angle of view the same as focal length?
No. Focal length is a property of the lens alone, while angle of view depends on both the focal length and the sensor size behind it. That is why the same lens frames differently on different cameras.
Related calculators
This calculator is for educational purposes. Double-check important results before acting on them.