The formula to calculate Watts (\(W\)) from Lumens (\(lm\)) is:

\[ W = \frac{lm}{lm/W} \]

Where:

• \(W\) is the power in watts.
• \(lm\) is the luminous flux in lumens.
• \(lm/W\) is the luminous efficacy in lumens per watt.