Lumens to watts
Lumens to watts: use luminous flux, luminous efficacy. Review the formula, worked example and calculation steps.
Inputs
Use the units shown—
Enter your values and select Calculate.
Formula & explanation
Power = Φ/efficacy
Variables & units
- Luminous flux
- lm · minimum 0, maximum 1000000000000
- Luminous efficacy
- lm/W · minimum 0.000001, maximum 1000000000000
Worked example
Change the supplied example values to match your circuit.
Assumptions
Uniform flux over the supplied area or cone. Distance assumes a point source and normal incidence. Supply the actual efficacy of your light.
Formula version 1.0.0. JavaScript floating-point arithmetic applies. Results display up to 6 decimal places; stored values retain available precision. Use the units shown.
Practice with an example
Use the default input values to find the answer. The reset icon restores those values.
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