IQ Score Ranges and What Each One Means

IQ scores are usually reported alongside a label — "Superior", "High Average", and so on. The labels are convenient, but the boundaries between them are conventions, not natural divisions. What actually matters is the percentile: how many people score below a given number.

The shape behind the numbers

IQ scores are constructed to follow a normal distribution — the symmetrical bell-shaped curve. This is not something discovered about human minds; it is built into the scoring process. Raw test performance is mathematically transformed so that the resulting scores take this shape, with a mean of 100 and, on the Wechsler scale used almost everywhere today, a standard deviation of 15.

That shape produces a few consequences worth memorising, because they explain everything else on this page:

• About 68% of people score between 85 and 115 (within one standard deviation).
• About 95% score between 70 and 130 (within two).
• About 99.7% score between 55 and 145 (within three).

The curve is steep in the middle and very flat at the edges. Most people are clustered near the centre, and scores become rare extremely quickly as you move outward. This is why a 10-point difference means something quite different at the centre than at the edge — see the last section.

The score ranges

The table below uses the classification scheme common to Wechsler-family tests, with approximate percentiles. "Percentile" here means the percentage of the reference population scoring at or below that range.

Notice that the middle band alone accounts for roughly half of everyone. "Average" is not a consolation category — it is where most people genuinely are, by construction.

What each band actually means

90–109 — Average

Half the population falls in this 20-point window. Someone scoring 95 and someone scoring 105 are not meaningfully different in reasoning ability; the gap between them is well within the measurement error of most tests. This range covers the great majority of successful careers, degrees and creative work.

110–129 — High Average and Superior

Roughly one person in four scores above 110, and about one in ten above 120. Scores in this range are typical among people who have completed demanding academic programmes. The relationship runs both ways, though: education itself develops the skills these tests sample, so a high score is as much a reflection of accumulated practice with abstract reasoning as a cause of it.

130 and above — Very Superior

About 2% of people score at or above 130 — two standard deviations from the mean. This is the threshold used by Mensa for membership. Above this point the numbers get slippery fast: scores above roughly 145 are difficult to measure reliably, because standard tests contain too few items at that difficulty to discriminate meaningfully. Very high reported scores should be treated with caution regardless of their source.

70–89 — Low Average and Borderline

Roughly one person in four scores below 90. Scores here are associated with more difficulty in conventional academic settings, but they say very little about an individual's capability in practical, social or vocational domains, which these tests do not sample.

Below 70

A score below 70 is one of several criteria clinicians consider when assessing intellectual disability — but only one. Formal diagnosis also requires evidence of significant limitations in adaptive functioning (everyday practical, social and conceptual skills), and it is never made on the basis of a test score alone, let alone an unsupervised online one. If a low score concerns you, a qualified psychologist is the right next step.

Percentiles are more informative than labels

A label tells you which box you landed in. A percentile tells you how the population is distributed around you, which is almost always the more useful fact:

• IQ 100 — higher than about 50% of people
• IQ 110 — higher than about 75%
• IQ 115 — higher than about 84%
• IQ 120 — higher than about 91%
• IQ 125 — higher than about 95%
• IQ 130 — higher than about 98%
• IQ 140 — higher than about 99.6%

Percentiles also expose how misleading equal score gaps can be. Moving from 100 to 110 takes you past roughly 25% of the population. Moving from 130 to 140 — the same 10 points — takes you past only about 1.6%. Near the tails, each additional point is buying far more rarity, which is exactly why high-end scores are so hard to measure precisely.

Always check the standard deviation

Two tests can both report "IQ 132" and mean quite different things, because not every scale uses SD 15:

• SD 15 — the Wechsler scale (WAIS, WISC). The modern default, and what this site uses.
• SD 16 — older Stanford–Binet forms. A score of 132 here sits at roughly the same percentile as 130 on an SD-15 scale.
• SD 24 — used by the historical Cattell III B. Scores on this scale look dramatically inflated next to Wechsler scores.

If someone quotes a striking number without naming the scale, the number cannot be interpreted. This is a common source of inflated claims online.

Reading your own result

Treat any single score as the centre of a range rather than a precise value. Even professionally administered tests report confidence intervals spanning several points in each direction, and an unsupervised online test — taken without a proctor, on unknown hardware, in unknown conditions — carries considerably more uncertainty than that.

The practical reading of a result is directional: whether you are broadly around the middle, noticeably above it, or noticeably below it. Distinctions finer than that are usually noise.