LOCAL ENGINEERING ESTIMATE

Beam diameter

Estimate the width defined by a stated full beam angle at a distance.

FORMULA & LIMITS

Understand the model

D = 2d × tan(θ / 2)

The angle may describe FWHM, not the outer edge of illumination. Real beams require a photometric distribution and the actual source geometry.

Changing an input invalidates the previous result. Check units before calculating again.