IQ questions, answered
Short, direct answers to the questions people ask most about IQ. Each page leads with the answer, then explains it with sources.
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Scores and ranges
- 01What is a good IQ score?Above 100 is above average. 110 and up is High Average or higher.
- 02What is a normal IQ range?85 to 115 holds about 68% of people. 90 to 109 is labeled Average.
- 03What IQ is above average?Above 100 beats the mean. 110 starts the High Average band.
- 04What IQ is considered low?The lower WAIS-IV labels, and why a label is not a diagnosis.
- 05Why is the average IQ 100?By design: each age group is scaled to a mean of 100.
- 06Is an IQ score a percentage?A standard score, not a percent. The percentile is separate.
- 07How is IQ calculated?Compared with your age group, then set on a mean-100 scale.
- 08What is the average IQ by age?100 at every age, by design. Raw abilities move; the score does not.
- 09What is the lowest possible IQ score?Every test has a floor. 55 is about 1 in 740 or lower.
- 10What does a borderline IQ mean?The WAIS-IV label for 70 to 79. A score band, not a diagnosis.
- 11What IQ is considered intellectual disability?Around 70 to 75, plus adaptive behavior, before age 22.
- 12What is an IQ score out of?Nothing: 100 is the average, not the maximum.
- 13Can IQ scores have decimals?The scale is continuous. The error makes decimals meaningless.
- 14Is IQ interval or ratio data?Interval: equal steps, no true zero.
- 15What is a Full Scale IQ?The overall score, built from seven subtests.
- 16What is a scaled score?Mean 10, SD 3: the subtest scale behind IQ reports.
- 17What was the original IQ formula?Mental age / age x 100, and the deviation IQ that replaced it.
High scores and Mensa
- 01What is considered a high IQ?120 and up is Superior, 130 and up Very Superior.
- 02What percentage of people have an IQ over 130?About 2.3%, roughly 1 in 44. Plus 120, 140, 150 and 160.
- 03What IQ is considered genius?No official cutoff. The top WAIS-IV label starts at 130.
- 04What IQ do you need for Mensa?The 98th percentile: about 131 on the standard scale.
- 05Is a Mensa test an IQ test?Approved, supervised tests, and a cutoff at the 98th percentile.
- 06What is the highest possible IQ score?Every test has a ceiling. Past it, the numbers stop meaning much.
- 07What is Mensa?A high-IQ society founded in 1946, open to the top 2%.
- 08Can you take the Mensa test online?Proctored online in the UK; in person in the US.
- 09Does Mensa tell you your IQ?A qualify-or-not result, not an IQ number.
Tests and accuracy
- 01Are online IQ tests accurate?Estimates, not diagnoses. What separates a careful test from a toy.
- 02Are IQ tests reliable?Full-scale scores: very. Single indexes and subtests: less so.
- 03Can IQ tests be wrong?Measurement error, conditions, practice and old norms.
- 04How accurate is an IQ score?Every score is a range. Clinical tests: about plus or minus 5.
- 05Why do IQ scores differ between tests?Different scales, norms and tasks, plus measurement error.
- 06What kinds of questions are on an IQ test?Six common puzzle types, with free examples of each.
- 07What is a nonverbal IQ test?Shapes and patterns instead of words. What that changes.
- 08Can you fail an IQ test?No pass mark. Every score is a position on the curve.
- 09How can I find out my IQ?A psychologist for an official score, a careful test for an estimate.
- 10Can you take an IQ test for free?Free to take is common. Check what the result costs first.
- 11Why are IQ tests renormed?Average performance drifts. New norms keep 100 meaning average.
Try one · Spatial Reasoning
Which option is the same shape, only rotated?
Tap the option you think is right, or show the answer.
Show the answer
Option 1 is the original figure turned a quarter turn counterclockwise.
How to solve it
- Pick a landmark: the marked cell or the end of the longest arm.
- Turn the figure in your head and watch where that landmark goes, and which side the other cells end up on.
- Turning the figure a quarter turn counterclockwise gives option 1.
- Each of the other options is a mirror image: flipping it over would match, but no turn does.
That was 1 puzzle. The full test has 25.
Taking an IQ test
- 01What is an IQ test?Standardized tasks, age norms and a score centered on 100.
- 02How long does an IQ test take?From about 12 minutes online to an hour or more in a clinic.
- 03Are IQ tests timed?Some race the clock, some do not. Test by test.
- 04How much does an IQ test cost?Clinic, Mensa and online options, with real example prices.
- 05Who can give an IQ test?Qualified professionals, under publisher rules.
- 06At what age can a child take an IQ test?From about age 2, with the right test.
- 07How often can you take an IQ test?Repeats inflate scores. Mensa allows one every eight weeks.
- 08Can you study for an IQ test?Familiarity helps a little. Here is how to prepare sensibly.
Change, age and genes
- 01Can your IQ change?Retests, measurement error and generations: what moves a score.
- 02Can you increase your IQ?Practice lifts test scores a little. That is not the same thing.
- 03Does retaking an IQ test raise your score?About 4 points on average, more with the same questions.
- 04Does IQ decline with age?The score is age-normed. Some raw abilities change, others grow.
- 05At what age does intelligence peak?Speed peaks early. Vocabulary and knowledge keep rising.
- 06Is IQ genetic?Heritability rises with age. It describes groups, not one person.
- 07Are people getting smarter?About 3 points per decade for most of the 20th century.
- 08Is the average IQ falling?A small reversal in some countries, slowing gains in others.
- 09Can a child's IQ change?Young scores shift. Schooling helps. Rank is fairly stable.
- 10Does education increase IQ?About 1 to 5 IQ points per extra year of school.
- 11Does reading make you smarter?Identical twins suggest learning to read lifts later reasoning.
- 12Does learning music make you smarter?About zero effect on general ability in well-designed studies.
- 13Does breastfeeding increase IQ?The largest randomized trial found a modest verbal IQ gain.
What IQ means
- 01What is IQ?A standard score: 100 is average for your age, 15 points is one SD.
- 02What does IQ stand for?Intelligence quotient: a 1912 name for a modern standard score.
- 03Who invented the IQ test?Binet and Simon in 1905, then Stern, Terman and Wechsler.
- 04Is IQ the same as intelligence?A measurement of some abilities, not the whole of a mind.
- 05Does IQ predict success?Real correlations across groups. Weak forecasts for one person.
- 06Is IQ just pattern recognition?Patterns are one part. Full tests sample five areas.
- 07Is IQ based on knowledge?Crystallized knowledge plus fluid reasoning.
- 08Is IQ related to memory?Working memory and reasoning travel together, but are not the same.
- 09How many things can working memory hold?About four chunks, not seven.
- 10Can smart people be irrational?High ability does not protect against many thinking biases.
- 11What is cognitive ability?The mental skills behind learning and reasoning, and how they are measured.
- 12What is twice-exceptional?High ability plus a disability, each able to hide the other.
- 13Does ADHD affect IQ?Not diagnosed by IQ. Average gaps, wide overlap, and 2e.
- 14Is autism linked to IQ?A spectrum that spans every level of measured ability.
Free tools: IQ percentile calculator · Percentile to IQ converter · IQ score chart
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