Luminous Intensity

Luminous flux (lumens) is the total perceived light output. Luminous efficacy (lm/W) measures how efficiently electricity is converted to visible light

The calculator uses the standard published formula for luminous flux. Results are accurate to the precision of the inputs you provide. For financial, medical, or legal decisions, always verify with a qualified professional.

This calculator works with inches, watts. You can enter values in the units shown — the calculator handles all conversions internally.

The core formula is: Lumens = Watts × Efficacy (lm/W). Each step in the calculation is shown so you can verify the result manually.