IQ Score Chart: Full Range, Classifications & Percentiles (2026)

The IQ Score Chart

Most modern IQ scales are standardized around an average score of 100 with a standard deviation of approximately 15 points. That means scores become progressively less common as they move farther above or below 100.

Classification terminology can vary between test publishers and editions. The percentile figures above are rounded estimates based on a normal distribution with a mean of 100 and standard deviation of 15.

For an exact score-by-score lookup including rarity expressed as "1 in X", see our IQ Percentiles and Rarity Chart .

IQ Score Comparison Chart: Compare Scores, Percentiles & Rankings

The chart above groups scores into broad ranges. This IQ score comparison chart goes further by showing individual scores in 5-point intervals, their approximate percentile and how far each score sits above or below the average IQ of 100.

For example, an IQ of 115 is approximately one standard deviation above average, while an IQ of 130 is approximately two standard deviations above average.

Percentiles are approximate and assume a normal IQ distribution with mean 100 and standard deviation 15. Extreme scores should be interpreted cautiously because test ceilings, norm samples and measurement error matter more at the ends of the scale.

How Common IQ Scores Compare

One of the easiest ways to understand the IQ scale is to compare several common reference scores side by side.

IQ Score Lookup: Compare Your Score

Enter an IQ score below to see its approximate percentile, classification and distance from the standardized average of 100.

What Each IQ Score Range Means

How IQ Scores Map to the Bell Curve

IQ scores are designed to follow an approximately normal distribution, commonly called a bell curve. Most scores cluster near 100, while very high and very low scores become progressively less common.

• Around 68% of scores fall between 85 and 115, within one standard deviation of the mean.
• Around 95% fall between 70 and 130, within two standard deviations.
• Around 99.7% fall between 55 and 145, within three standard deviations.

For a dedicated visual explanation, see our IQ Bell Curve page.

IQ Score Comparison by Test Scale

Two IQ numbers are not always directly comparable. Different historical tests and scoring systems have used different standard deviations, meaning the same percentile can be represented by a different numerical IQ score.

This is why an older test report and a modern report can contain different numerical IQ scores while representing a similar percentile position.

Learn more in our IQ scale guide, Wechsler IQ test guide and Stanford-Binet IQ test guide.

Why IQ Percentile Matters When Comparing Scores

The numerical difference between two IQ scores does not directly tell you how common each score is. Percentile rank makes the comparison easier because it shows the approximate percentage of the norm group scoring at or below a particular level.

For example, moving from IQ 100 to IQ 115 is a 15-point increase, but it corresponds roughly to moving from the 50th percentile to the 84th percentile. Moving another 15 points to IQ 130 corresponds to roughly the 98th percentile.

This is why percentile and rarity become especially useful when comparing higher IQ scores. See the full IQ percentile and rarity chart for score-by-score detail.

Treat an IQ Score as an Estimate, Not a Perfectly Fixed Number

IQ test results should not be interpreted as infinitely precise. Standardized assessments commonly report a confidence interval around the obtained score because all psychological measurement contains some degree of measurement error.

In practical terms, two scores that differ by only a few points may not represent a meaningful difference. The test used, its reliability, testing conditions, age norms and other factors can all influence the reported result.

IQ Score Chart: Frequently Asked Questions