A summary of his accomplishments:
Scored a 760 on the SATM when he was 8 years old
Youngest winner of each of the medals of the international mathematical olympiad
Recieved his PhD when he was 21
Has recieved dozens of awards and prizes
h-index of 106, 90000 citations
I think it’s safe to say that Terence Tao is the best mathematician in the world, which translates to a math IQ of 200. He also performed very well on the ravens, he scored a 32 on the RAPM when he was 10, which is the 95th percentile for a white adult in the USA.
Given that a large mathematical composite test has a g-loading of about 0.77, Terence Tao has an IQ of about 173 with a standard error of roughly sqrt(1-0.77)*15 = 7.2
A commenter notes that he scores about 3.7 standard deviations below verbal in mathematical ability - though his mathematical ability is about 6.6 SD above the mean, so his relatively low verbal score isn’t particularly meaningful.
How does his verbal performance factor into this?
"Yet at age 8 years 10 months, when he took both the SAT-M and the SAT-Verbal, Terry scored only 290 on the latter. Just 9% of college-bound male 12th-graders score 290 or less on SAT-V; a chance score is about 230. The discrepancy between being 10 points above the minimum 99th percentile on M and at the 9th percentile on V represents a gap of about 3.7 standard deviations. Clearly, Terry did far better with the mathematical reasoning items (please see the Appendix for examples) than he did reading paragraphs and answering comprehension questions about them or figuring out antonyms, verbal analogies, or sentences with missing words.
Was the "lowness" of the verbal score (excellent for one his age, of course) due to his lack of motivation on that part of the test and/or surprise at its content? A year later, while this altogether charming boy was spending four days at my home during early May of 1985, I administered another form of the SAT-V to him under the best possible conditions. His score rose to 380, which is the 31st percentile. That's a fine gain, but the M vs. V discrepancy was probably as great as before. Quite likely, on the SAT score scale his ability had risen appreciably above the 800 ceiling of SAT-M.
If his SAT-V score continues to increase 90 points per year (it may not go up quite that fast), he will reach the average of beginning undergraduates at Harvard and Yale by age 12, and the top of the scale (800) by 14. He was not nearly there at age 9, however! That is one of the main reasons why I counseled the Taos to hold off the more verbally abstract school subjects, including "pure" mathematics, for a while, pending the natural growth of Terry's reading and verbal reasoning abilities."
https://web.archive.org/web/20100215233432/http://www.davidsongifted.org/db/Articles_id_10116.aspx