Rory Bidwell passed with flying colours, scoring 162 — the maximum given to under-18s on the intelligence test.
He is now one of the youngest members of the genius club Mensa.
It means he has a higher IQ than German-born physicist Einstein and black hole theorist Stephen Hawking, whose scores were both estimated at 160.
Rory, a Year 7 pupil at Great Torrington School, Devon, took the two-hour test in Exeter just a fortnight after his 12th birthday.
His mum, Abi, who also took the test and scored an impressive 129, told him she had signed him up for it only on the day.
Rory told The Sun: “Only a few of the questions were challenging and some were quite easy.
“When I first got the results I didn’t understand what it meant, but then I realised it was actually a brilliant result.”
The youngster, whose favourite subject is maths and wants to study at Oxford or Cambridge, said being clever felt good but he does not know what he wants to do when he is older.
Abi, 40, said: “He is blessed with an incredible brain.”
The mum of three joked: “He even had time to go for a toilet break.
“When he was two he did a 100-piece puzzle by himself.
“Then he started doing secondary school algebra in Year Two.”