Given the evidence, Luffy's IQ could easily be anywhere between 90 and 130. This would make his intelligence at least average and maybe a little above average, although not quite genius-level. His morality, choices, actions and accomplishments should say as much about him.
Although not often seen in the series, One Piece author Eiichiro Oda has confirmed Beckman to have the highest IQ in East Blue.
Sanji - 120. he s intelligent but not a scientist; Brook - 110.
Roronoa Zoro
At the very least, Zoro is a little smarter than his captain. He knows how to calculate a little, (such as correctly answering Luffy's "108 x 2" question), has made a plan to defeat Pica, and has correctly guessed that Baroque Works lured them into a trap.
She is very wise and very patient in everything. Robin does not play a specific role in the ship, but she can foresee what can be found somewhere and that (in her own words), is of advantage to others. Luffy considers her a very intelligent member.
Given the evidence, Luffy's IQ could easily be anywhere between 90 and 130. This would make his intelligence at least average and maybe a little above average, although not quite genius-level.
Luffy may not be the smartest character in One Piece, but he has almost unrivaled instincts and great emotional intelligence. On this occasion, however, Luffy also showcased a quick and deep understanding of a complex situation that proves the character has grown a lot since his debut.
I would say Robin overall. In terms of intelligence such as education then definitely she spent her entire childhood reading and learning. Even now you see her generally reading a book while on the Sunny.
115 to 129: Above average or bright. 130 to 144: Moderately gifted. 145 to 159: Highly gifted. 160 to 179: Exceptionally gifted.
Garry Kasparov (IQ Level = 194)
Garry Kimovich Kasparov, a Russian chess grandmaster, has an IQ level of 194. Apart from being a former world champion in chess, he is also a writer and political activist, and commentator. Kasparov ranked No. 1 from 1984 to his retirement in 2005.
Goku-76, Probably higher than you thought but he often proves he can do smart things too. Vegeta-106, About average intelligence and is never shown to have superior intelligence. Piccolo-115, Often portrayed to have clever moments and leads the Z fighters in a smart way. Bulma-190, No surprise Bulma's REALLY smart.
Of the members of Team Seven, barring Kakashi, we can say that each of them have their own intelligences. As a formality though, the franchise puts Sakura's IQ at 174, Sasuke's at 100 and Naruto's at 90, just below the human average.
1 Shikamaru Nara
He was believed to have an IQ over 200 by his teacher, Asuma, and could defeat opponents significantly stronger than he was, provided there was even the slightest chance of victory.
Michael Kearney - (IQ - 200–325)
He is known for setting world records as the youngest man to graduate and teach at the university, as a teenager and with an IQ between 200 and 325. He completed his bachelor's degree at the University of South Alabama, USA, at age 10.
There's no record of the lowest IQ ever. However, the lowest IQ score possible is zero. Can someone actually get this low of a score? In theory, yes.
Senku Ishigami (Dr. Stone) It would be completely fair to start the list with a science nerd. Senku Ishigami is believed to possess an IQ of 180 to 200, making him a highly gifted being.
Over the years, he's faced adversity in many forms and overcome them with his many power-ups. Currently, Luffy is strong enough to fight the strongest of the Yonko in a one-on-one battle, making him extremely capable.
Given that he can nullify Luffy's powers as well as use the earth-destroying quakes, Blackbeard can certainly defeat Yonko Luffy.
Luffy's real-world nationality analogue is Brazilian.