Scale of IQ Scores: Ranges, Percentiles & Chart (2026)
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The IQ score scale uses a mean of 100 and standard deviation of 15 (SD-15). Each 15-point band ≈ one percentile chunk on the bell curve—see chart and ranges below.
Who This Article Is For
27K+ monthly searches on IQ scale and chart queries (low–medium SEO difficulty).
Key Takeaways
SD-15: 68% of scores fall between 85 and 115.
SD-16 (Stanford-Binet) uses a wider spread—compare scores carefully.
Percentiles beat labels like 'bright' or 'dull.'
Full chart: IQ score chart pillar page.
Direct Answer: What Is the Scale of IQ Scores?
Most modern IQ tests use a **deviation IQ scale**: mean = 100, standard deviation = 15. A score of 115 is one SD above mean (~84th percentile); 85 is one SD below (~16th percentile).
For a visual breakdown, see the canonical IQ score chart—this guide answers 'scale of IQ scores' search phrasing.
IQ Measurement Ranges (Quick Reference)
Labels vary by publisher; percentiles are more comparable than words.
- Below 70 — often intellectual disability range (clinical context required)
- 70–85 — low average
- 85–115 — average (bulk of population)
- 115–130 — high average / superior
- 130+ — gifted / very superior (Mensa-style thresholds)
SD-15 vs SD-16
Mixing scales causes errors. Read SD-15 vs SD-16 before comparing scores from different batteries.
Sources & further reading
External links open authoritative references used to fact-check this article. GuideIQ summarizes research; always read primary sources for clinical or legal decisions.
- APA — Intelligence
Definitions and limits of IQ testing.
- CDC — Healthy brain
Cognitive health across the lifespan.
Common Interpretation Mistakes
Reading a search-result snippet as if it were a verified fact.
Treating estimated IQ figures as official test scores when no published score exists.
Ignoring the broader parent guide that explains the full evidence and context.
90-Day Action Plan
Start with the direct answer, then read the linked parent article for the complete context.
Separate verified evidence from estimates, self-reported claims, and internet repetition.
Use the related links to compare this topic with adjacent IQ score, profession, or state-ranking pages.
Frequently Asked Questions
What is a normal IQ range on the scale?
Roughly 85–115—about two-thirds of the population on SD-15 tests.
Is 120 high on the IQ scale?
Yes—around the 91st percentile on SD-15; see 120 vs 130.
Where is the full IQ chart?
See IQ score chart and IQ percentile chart.
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