Angular Size Calculator

Angular diameter of an object from its size and distance, or size from angle and distance.

How to use the Angular Size Calculator

Fill in what you know of: Physical size, Distance, Angular size — leave the unknown empty.
The results (Angular size, Size, Distance) are calculated instantly as you type.
Use “Copy link” to share the calculation with the same input values.

Formula

δ = 2·atan(D / 2d)