How to convert candle lumins to watts?

Question

I have a 300,000 candle light that I need to estimate the watts in order to use appropriately.

Answer 1

Lumens and Watts are just photometric and radiometric terms for the same thing: optical power or flux.   The only difference is that photometry (luminous power) takes into account human perception and accounts for the sensitivity of the eye to different colors.   This can make it difficult to convert between the two unless you know the spectra of the bulb.

By definition,  at the peak sensitivity of the eye (green 555nm) 1 Watt equals 680 lumens.

It would make the most sense to talk about lumens with a flashlight, because what you really care about is the perceived "brightness", not the true optical power.

Answer 2

you cannot convert them like this, consider the incandescent light versus the compact florescent. a 100 watt incandescent light is about as bright as a 27 watt compact florescent light. However, if you know the voltage at which it runs, you can plug it in and use an amp meter to determine the current it draws, then, simply multiply the volts by the amps in order to find watts.

Answer 3

there is no direct conversion. If you know the efficiency of the light, you may be able to convert with some math.