THE CHART
Every range, in three classification systems
RANGELABELPERCENTILESSHAREROUGHLY
145+Highly gifted+99.9th+0.13%1 in 741
130–144Gifted98th – 99.9th2.1%1 in 47
120–129Superior91st – 98th6.8%1 in 15
110–119High average75th – 91st16.1%1 in 6
90–109Average25th – 75th49.5%about half
80–89Low average9th – 25th16.1%1 in 6
70–79Borderline2nd – 9th6.8%1 in 15
below 70Extremely lowbelow 2nd2.3%1 in 44
This site's labels: Wechsler bands with gifted tiers on top. Shares and percentiles are computed exactly from the normal curve; publishers' labels vary, but the percentile is what should drive interpretation.
WHY THESE CUT-OFFS
The boundaries come from the curve, not from clinicians
Every major line sits a whole number of standard deviations from 100. Tap one.
130 = 100 + 30 · +2 SD97.7th percentile. The conventional line for 'gifted' and Mensa's cut-off.
A SINGLE SCORE IS NEVER THE WHOLE STORY
"About 120, probably 115–125" is honest. "120" isn't.
The WAIS-IV reports a standard error of measurement around 2.5 points, so a measured 120 has a 95% interval of roughly 115–125. Online tests usually carry 5–8 points of error, which can mean ±10–15 at 95%. The chart above draws that interval around your score.
HOW TO READ YOUR SCORE HONESTLY
1Treat the score as a range: add and subtract the interval for your test type.
2Look at the subscores, not just the composite: 130/130/110/110 and 120/120/120/120 are different people.
3Check the conditions: tired, stressed or distracted? Retest under better ones before concluding anything.
4Don't over-interpret: one score is a snapshot of one kind of thinking on one day.
DIFFERENT TESTS, DIFFERENT SCALES
Bring an old score onto this chart
Scores from different eras or publishers aren't directly comparable. Pick the scale your score came from.
SD ABOVE MEAN+2.00
PERCENTILE98th
ON THIS CHART130
WHAT AN IQ SCORE DOESN'T MEASURE
A reference for test performance, not a measure of worth
Practical judgementGood decisions in messy, real-world situations.
Emotional intelligenceReading others, regulating yourself, managing relationships.
CreativityOnly weakly related to IQ above about 120.
Conscientiousness & gritArguably better predictors of life outcomes.
Domain expertiseHigh IQ, and nothing known about carpentry or music theory.
Curiosity & motivationStrong predictors of intellectual achievement, independent of IQ.
HOW THESE CONVENTIONS EMERGED
From labels to ratios to standard scores
The Wechsler-Bellevue scored adults against their own age group with SD 15: the deviation IQ every chart now uses.Open the archive page →
WHAT EACH SCORE MEANS · ONE PAGE PER SCORE
GO DEEPER
01The IQ scale explainedHow mean 100 and SD 15 are built, deviation vs ratio IQ→02IQ scores explainedWhat a score is, how it's normed, online vs clinical→03IQ percentile chartEvery score to a percentile, and back→04IQ score convertersBetween scales, percentiles and z-scores→05What is the average IQ?Why it's 100, by age, country and university→06Crystallized vs fluid intelligenceThe two broad abilities behind IQ→
QUICK ANSWERS
What is a normal IQ?85–115 is the average range and covers about 68% of people; 70–130 covers about 95%.
What does 120 mean?About the 91st percentile, in the 'superior' band on most systems: roughly 91 in 100 score lower.
What's the highest possible IQ?No fixed maximum. The WAIS-IV reports up to 160; the Stanford-Binet 5's extended norms go further, but scores above about 145 are increasingly extrapolated. Treat claims above 180 with extreme scepticism.
Why SD 15?Convention. Wechsler standardised SD 15 in 1939 and the major batteries followed. On SD 24, 130 is only the 89th percentile.