0.1 %
Smarter than 0.1% of people
Extremely Low
Well below average, often benefits from extra support
🏛️ Mensa cutoff 130 — 90 points away
🌍 In the United States (national average ≈ 98, an estimate from test samples), an IQ of 40 is in the top 99.9%.
❓ FAQ
Is an IQ of 40 a good score?
An IQ of 40 falls in the "Extremely Low" range and is higher than 0.1% of the population.
What percentile is an IQ of 40?
An IQ of 40 sits at the 0.1th percentile — the top 99.9% of the population.
Can you join Mensa with an IQ of 40?
Mensa requires roughly IQ 130 (top 2% on SD15); 40 is 90 points below the cutoff. Practice and a supervised test may close the gap.
How many people have an IQ of 40 or higher?
Roughly 8,099,743,343 people worldwide — about 99.9% of 8.1 billion.