IQ Score Distribution: What Percentage of People Have Your IQ?

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The IQ Bell Curve

IQ scores are designed to follow a normal distribution — the famous "bell curve" — with a mean of 100 and a standard deviation of 15. This means that in any given population, the majority of people score near the average, with progressively fewer people at the extremes. The distribution is symmetrical: an equal number of people score above and below 100.

Understanding exactly where any score falls in the population requires knowing two things: the mean (100) and the standard deviation (15). Each standard deviation above or below the mean corresponds to a percentile rank that tells you what percentage of the population you score above.

IQ Score Distribution Table

IQ Score Range	Classification	% of Population	Percentile Range
Above 145	Profoundly Gifted	0.1%	Top 0.1%
130–145	Highly Gifted / Very Superior	2.1%	98th–99.9th
120–129	Superior	6.7%	91st–97th
110–119	High Average	16.1%	75th–90th
90–109	Average	50.0%	25th–74th
80–89	Low Average	16.1%	9th–24th
70–79	Borderline	6.7%	2nd–8th
55–69	Mild Intellectual Disability	2.1%	Below 2nd
Below 55	Moderate–Profound Disability	0.1%	Below 0.1%

How to Interpret Your Percentile

Your percentile rank tells you what percentage of the general population you scored above. An IQ of 115 corresponds to approximately the 84th percentile — meaning you scored higher than 84% of the population. An IQ of 130 puts you at the 98th percentile — above 98% of people.

Key reference points on the bell curve:

• IQ 85: 16th percentile — scores higher than 16% of people
• IQ 100: 50th percentile — exactly average
• IQ 115: 84th percentile — within the top 16%
• IQ 130: 98th percentile — within the top 2%
• IQ 145: 99.9th percentile — approximately 1 in 1,000 people
• IQ 160: approximately 1 in 30,000 people

The Standard Deviation Rule

Because IQ is normally distributed with SD=15, the standard statistical properties of normal distributions apply:

• ~68% of people score between 85 and 115 (within 1 SD of the mean)
• ~95% score between 70 and 130 (within 2 SDs)
• ~99.7% score between 55 and 145 (within 3 SDs)

This means an IQ of 145 is genuinely exceptional — approximately 1 in 1,000 people. An IQ of 160 (5 SDs above the mean) corresponds to roughly 1 in 3.5 million — though measurement reliability at these extremes becomes questionable.

Why Average IQ Varies by Country and Era

IQ tests are periodically "re-normed" — the average is reset to 100 for new populations. This is necessary because raw scores have risen dramatically over time (the Flynn Effect). Without renorming, modern populations would score far above historical baselines.

When comparing IQ across countries, different populations have been measured against different national norms. An IQ of 100 in Finland has the same within-country meaning as an IQ of 100 in South Korea — it simply means "average for that country" — but the populations may differ substantially in absolute test performance.