Calculate Projecot Distance Beam Angle and Beam Size Image Diameter

Ever needed to project a gobo or image to be a specific size but dont know what beam angle you need? Want to know how big the pool of light will be from your projector? Want to calculate how far away you need to place a profile light such as ETC Source 4?

Fill in any two values you know and click the button next to the unknow value, you will have the answer.

Throw Distance Meters
Beam Angle Degrees
Image / Beam Size Meters

This little calculator will work for all lantern manufactures, whether it be Selecon Pacific, an ETC Source 4 Profile, an Robert Juliat Followspot, Robe Moving Light - its only trigonometry.