Lumens to Millicandela Calculator

Calculate the millicandela (mcd) rating of a light source given its total lumens and beam spread.

I_v(mcd) = [Φ_v(lm) / (2π(1 - cos(½θ)))] × 1000
10 lumens with a 30° angle ≈ 14,440 mcd

How do I convert lumens to millicandela?

First, convert lumens to candela using the beam angle formula: Candela = Lumens / [2π(1 - cos(½θ))]. Then, multiply the result by 1,000 to get millicandela (mcd).

What is millicandela (mcd)?

A millicandela is one-thousandth of a candela. It is a common unit for describing the brightness of small indicators like LEDs.

Why do I need the beam angle?

Lumens measure total light output, while candela measures intensity in a specific direction. The tighter the beam angle (e.g., 15° vs 120°), the higher the millicandela rating will be for the same amount of lumens.