Lumens to Candela Calculator

Lumens to Candela Calculator

It is a conversion calculator that converts the luminous flux in lumens (lm) to the luminous intensity in candela (cd). Since lumens and Candela are of different quantities, they cannot be converted directly and requires the apex angle in degrees. The initial step is to enter the value of luminous flux in lumens. Proceed to the next text field where you enter the apex angle in degrees. Afterwards, click on the ‘Calculate’ button to initiate the conversion. If you want to perform new calculations, the ‘Reset’ button will be useful in erasing all previous data in the text fields. Your luminous intensity result in candela will be displayed in the bottom platform of the calculator below the two controls.

For example;

If the luminous flux in lumens is 455 lm with an apex angle of 56°, determine the luminous intensity in candela.

Solution

When using the calculator, you will first enter 455 in the luminous flux in lumens text field and apex angle respectively. Afterwards, click the ‘Calculate’ button. The luminous intensity result in candela will be;

= 618.65877751 (cd)

This calculator uses a particular formula in performing the calculations.

Formula of calculating lumens to candela

Iv (cd) = фv (lm) / Ω (sr), which means that for a uniform isotropic light source, the luminous intensity in candela is calculated by dividing the luminous flux in lumens by the solid angle in steradians.

Ω (sr) = 2∏ (1 – cos (Ө/2)), which means that the solid angle in steradians is calculated by multiplying two times pi by; one minus the cosine of half the cone apex angle in degrees.

Iv (cd) = фv (lm) / 2∏ (1 – cos (Ө/2)), where the luminous intensity in candela is calculated by dividing the luminous flux in lumens by two time pi multiplied by; one minus the cosine of half the cone apex angle in degrees.