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Lumens to Watts Calculator

Convert luminous flux (lumens) and luminous efficacy to power (watts).

Input Data

Input Luminous flux Φ.
lm
Input Luminous efficacy η.
lm/W

Results

8W
P = Φ / η = 800 lm / 100 lm/W = 8.000000 W

At a glance:Lumens to Watts Calculator: enter parameters to compute results; complements related calculators.

Formula

P = Φ / η

Φ: luminous flux (lm), η: luminous efficacy (lm/W), P: power (W)

How to Use

  1. Enter luminous flux Φ (lumens).
  2. Enter luminous efficacy η (lm/W).
  3. Get power P (watts).

Case Studies

Φ = 800 lm, η = 100 lm/W

P = 800 / 100 = 8 W (typical of modern LEDs).

FAQ

Luminous efficacy?

Lumens produced per watt; higher is more efficient.

Relation to illuminance?

With area, Φ gives illuminance (see lumens-to-lux).

Related Tools

References

Content review: Calculatorism Science Team. Formula and numeric tests verified; results for reference only.

Found a problem with the results?

If this calculator's result is wrong, or you have any question about the calculation logic, please let us know. You are viewing:Lumens to Watts Calculator（/light/lumens-to-watts）。