Hi all, first post in here for a long time!

I'm looking to buy a more powerful headlight for my bike, since the light I have at the moment is more to make sure people see me rather than to see where I'm going. The problem I'm running across is that there seem to be several different units used to measure how much light a headlight produces. I've seen lumens, lux, and candlepower all used to describe lights, and frankly they've got me stumped.

Is it just a matter of multiplying by some constant, like converting between miles and kilometres?

If not, what's the deal?

Thanks in advance!