I've been researching this lately, and I have seen estimates of Einstein's IQ which range from 160 to 240. The whole IQ thing is pretty much a hoax, in lots of ways. If you look at the history, the IQ test was only supposed to be to test retarded children, so that below average intelligence could be assessed.

There was not any intention, ever, of testing "genius".

When you think of it, why test genius? Why not test God, while you are at it? Why not test gravity by jumping off a cliff?

Eventually, it got to be popular to test for higher IQs, as well, with the IQ supposedly measuring a quotient of mental age divided by chronological age.

If that were the case, then Einstein (who didn't learn to speak until he was three) might have had an IQ of 50, based on some evaluations. On the other hand, I once scrawled in crayon on the wall of my room the phrase "Framberry Dolphi" (a French liquer whose name was stenciled on a box in my closet), at the tender age of 3. Gosh, Einstein couldn't even speak at 3, and I was already writing in French?! Wow!! I must have an IQ of at least 440, then, I guesstimate.

Don't get me wrong -- psychometry is helpful somewhat, but I have had many scars inflicted on me by people who bragged about their "wonderful IQs", trying to humiliate me, when I didn't know what mine was. The IQ can be an insidious trap of the ego, in many cases. I would sort of like to go back and rap them all over the head with a heavy lead pipe, and examine the "structural integrity" of their skulls, to see how "well engineered" their heads were (perhaps that should be another criterion of "IQ")....

IQs also change over age, sometimes. And, IQs can be depressed or inflated, by external stimuli. There are many opinions on the subject, and some have placed the highest IQ at 185, others at 220, and others at 300.

I scored a 195 on one test (the SAT, according to conversion tables), and I can personally attest that I hate the whole IQ test/score conversation a lot. It's not even clear what they measure, at all. Somebody like Marilyn Mach vos Savant studied for her tests, to achieve a 238 IQ, which seems utterly pointless, if you were striving to remain true to the original aims of the test.

On the other hand, I guess she proved that she isn't retarded....

And, also, it has lately been suggested that IQ has really 7 components, including the "kinesthetic" (relating to athletic coordination). If that is the case, then how could Einstein or Hawking be geniuses (especially Hawking)?

Modern IQ theory is still a lot of Bosch -- At least Einstein figured out some good equations, and did a little good Tensor Algebra!