Enter the distance, length, and angle into the calculator to determine the angular size of a triangle.

## Angular Size Formula

The following formula is used to calculate the angular size.

D = 2 * L * tan (a/2)

- Where D is the angular size
- L is the radius/length depicted below
- a is the angle depicted below

To calculate the angular size, multiply 2 times the length by the tangent of half the angle.

## Angular Size Definition

An angular size is a value of the length of a field of view.

## Angular Size Example

How to calculate angular size?

**First, determine the radius.**Measure the radius.

**Next, determine the angle.**Measure the angle.

**Finally, calculate the size.**Calculate the angular size using the equation above.

## FAQ

**What is an angular size?**

An angular size is a value of length that represents the total length of a field of view from a point of a triangle, a certain radius, and certain angle. This can be seen as D in the above depiction.