What is the range of a 5mw 650nm laser?

Question

I want to buy a laser pointer but I keep getting mixed info. So what is the actual distance it will go?

Answer 1

It goes forever until it hits something.  The beam isn't perfectly linear, so it expands and the luminous flux goes down with distance (like 1/r^2).  Also, a tiny bit gets absorbed or scattered by air, so the intensity goes down by a small exponential factor because of that.

Answer 2

Rays of light, whether from a laser or some other source, keep going in a straight line until they are reflected or absorbed by something, right out to infinity. The actual distance it will go is infinite, unlimited. The beam will spread according to the inverse square law, though, so the spot projected by a laser of that size will only be visible for a distance much shorter than infinity.