IQ 58: what it means and what to do next
An IQ of 58 is higher than about 0.26% of people, roughly 1 in 391 at or below. On a professional test that is in the extremely low range. On the Assessivo test, 58 means one correct answer out of 36, which is far below what random guessing produces, so it is far more likely to reflect a problem with the session than with your reasoning.
How far below average is 58?
An IQ of 58 is 42 points below the average of 100, or 2.8 standard deviations. About 0.26% of people of the same age score lower, the shaded sliver at the far left of the curve below.
On a test with a standard deviation of 16, such as older Stanford-Binet editions, the same result would be about 55, and on the Cattell scale, which uses 24, about 33. Why scales differ.
What an IQ of 58 tells you
Here is the maths. With four options per question, a person guessing blindly gets about nine of 36 right on average. The chance of getting only one or none right by pure guessing is about 1 in 2,400. So when a score of 58 comes from an online test, the usual explanation is time running out, a tab left open in the background or questions skipped, not a measure of ability.
On a professional test given one to one by a psychologist, a 58 means something different, and it is never read on its own. It would be weighed together with how the person manages communication, relationships and practical tasks, because that, rather than the score, is what decides whether there is an intellectual disability and what support would help.
How an IQ of 58 is classified
Different tests and manuals use different words for the same score, and the words have changed over time. Here is where 58 falls on each of the systems you are most likely to meet.
Sources: American Psychiatric Association, DSM-5 fact sheet on intellectual disability; World Health Organization, ICD-11, 6A00 disorders of intellectual development; Peltopuro, M. and others (2014), "Borderline intellectual functioning: a systematic literature review", Intellectual and Developmental Disabilities, 52(6), 419–443. WISC-V descriptors from Pearson's interpretive reports, as on our good IQ score guide.
Does 58 mean an intellectual disability?
A score of 58 on its own never makes a diagnosis. The American Psychiatric Association's DSM-5 describes intellectual disability as "approximately two standard deviations or more below the population, which equals an IQ score of about 70 or below", and requires three things together:
- Low intellectual functioning, confirmed by a clinical assessment and individually given, standardised testing.
- Difficulties with everyday adaptive skills in at least one of three domains: conceptual (language, reading, maths, memory), social (communication, judgement, friendships) and practical (personal care, money, work and school tasks).
- A start during the developmental period, in childhood or adolescence.
Severity is set by those everyday skills, not by the IQ number. That is why only about 1% of people have an intellectual disability (a 2011 meta-analysis of 52 population studies found about 10 per 1,000), even though about 2.3% score below 70 on the bell curve. Because tests have a margin of error, DSM-5 treats roughly 65 to 75 as the uncertain zone around 70.
Sources: American Psychiatric Association, DSM-5 fact sheet on intellectual disability; Maulik, P. K. and others (2011), "Prevalence of intellectual disability: a meta-analysis of population-based studies", Research in Developmental Disabilities, 32(2), 419–436; Hall v. Florida, 572 U.S. 701 (2014), which cites the DSM-5 range of 65 to 75.
Is your 58 accurate?
Low scores are the most fragile results on any test, because almost everything that goes wrong on the day pulls a score down. Common reasons include:
- Running out of time. On timed tests, including ours, an unanswered question counts as wrong.
- Nerves. A review of 238 studies found test anxiety consistently linked with lower scores.
- Tiredness. Sleep loss hits attention and speed hardest, which costs points against the clock.
- Language and format. Taking a test in a second language, on a small screen or in an unfamiliar format can lower a result without saying anything about reasoning.
What a 58 means on our test
On the Assessivo test, 58 means 1 correct answer out of 36. Every question has four options, so someone guessing every answer at random averages nine correct, a score of 78. Random guessing scores this low only about once in 2,420 attempts. The likeliest explanations are the clock, a refresh at the wrong moment or a very interesting phone, not your reasoning.
If any of this sounds like your session, retake the free IQ test when you are rested and have 25 quiet minutes. A score that moves a lot between attempts was never very solid.
Sources: von der Embse, N. and others (2018), "Test anxiety effects, predictors, and correlates: a 30-year meta-analytic review", Journal of Affective Disorders, 227, 483–493; Lim, J. and Dinges, D. F. (2010), "A meta-analysis of the impact of short-term sleep deprivation on cognitive variables", Psychological Bulletin, 136(3), 375–389. Guessing figures are worked out from the binomial distribution for 36 four-option questions.
What is the mental age for an IQ of 58?
The first IQ tests, for children, described performance as a "mental age": the age whose typical performance a child matched. IQ was mental age divided by real age, times 100. Run that old formula backwards and you get the figures below, for children only.
| Child's age | Performs like a typical child of about |
|---|---|
| 6 | 3 years 6 months |
| 8 | 4 years 8 months |
| 10 | 5 years 10 months |
| 12 | 7 years |
| 14 | 8 years 1 month |
For adults the idea doesn't work, which is why David Wechsler replaced it in 1939 with today's method: compare each person with others of the same age. An adult who scores 58 has an adult's knowledge, interests and experience. The score only says how their test performance compares with other adults'.
How common is an IQ of 58?
Line up 100 people of the same age and about 1 would score 58 or lower; the orange dot marks the place. In a city of a million, about 2,560 people would be at or below this level.
The bar shows the likely range on a professional test, about five points either way: 53 to 63, from the 0.09th to the 0.68th percentile.
How 58 compares with nearby scores
| IQ | Percentile | Classic label | Score this low or lower |
|---|---|---|---|
| 53 | 0.09th | Extremely low | 1 in 1,157 |
| 58 | 0.26th | Extremely low | 1 in 391 |
| 63 | 0.68th | Extremely low | 1 in 147 |
| 68 | 2nd | Extremely low | 1 in 61 |
Questions about an IQ of 58
What percentile is an IQ of 58?
An IQ of 58 is at about the 0.26th percentile: it is higher than about 0.26% of people of the same age, and roughly 1 person in 391 scores this low or lower.
Is 58 a low IQ?
Yes. 58 is 42 points, or 2.8 standard deviations, below the average of 100. On the classic Wechsler labels it is extremely low. A single score is an estimate with a margin of error of about five points, so 58 is best read as roughly 53 to 63.
Does an IQ of 58 mean intellectual disability?
Not on its own. 58 is in the range where an intellectual disability (called a learning disability in the UK) is considered, but a diagnosis also needs significant difficulties with everyday skills that began during childhood, assessed by a qualified psychologist.
What is the mental age for an IQ of 58?
Mental age is an idea from the earliest tests for children. By the old formula, a 10-year-old scoring 58 would perform like a typical child of about 5 years 10 months. For adults it has no meaning: modern IQ tests compare adults with other adults, and an adult who scores 58 is not like a child.
I scored 58 on an online IQ test. Is that accurate?
Probably not. On our test 58 means one correct answer out of 36, and pure guessing would average about nine, so a result this low usually means the timer ran out or questions were left unanswered. Retake it rested, with 25 uninterrupted minutes, before reading anything into it.
Related: the IQ range chart, what counts as an average IQ, what IQ measures and misses and how to tell if an online IQ test is accurate.
Behind a single score of 58 sit several separate abilities. Read about verbal reasoning, processing speed, fluid vs crystallized intelligence, abstract reasoning and spatial reasoning, or try the free pattern recognition test.
Information and support
If a professional assessment has given you, your child or someone you care for a score like 58, these organisations explain what it means in practice and what help is available.
Want a second reading?
Take the free Assessivo IQ test when you are rested and have 25 quiet minutes: 36 questions, and your estimated score and percentile as soon as you finish.
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