Is an IQ of 56 low?
Yes. An IQ of 56 is very low compared with the population: only about 0.17% of people, roughly 1 in 596, score this low or lower. It sits near the bottom of the range the World Health Organization links with a mild disorder of intellectual development, but that label also needs evidence about everyday life, not just a test score.
56 on the IQ bell curve
An IQ of 56 is 44 points below the average of 100, or 2.93 standard deviations. About 0.17% 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 53, and on the Cattell scale, which uses 24, about 30. Why scales differ.
Reading an IQ of 56
The World Health Organization's classification, ICD-11, describes a mild disorder of intellectual development as intellectual functioning and adaptive behaviour about two to three standard deviations below the mean, roughly the 0.1st to 2.3rd percentile. On the usual IQ scale that is about 55 to 70, so 56 is just inside its lower edge.
The same entry is notably hopeful about what this range means. It says people in it often find complex language and academic skills hard, but most master basic self-care, domestic and practical activities, and as adults can generally achieve relatively independent living and employment, with appropriate support. That is a long way from the bleak picture the number alone might suggest.
How an IQ of 56 is classified
Different tests and manuals use different words for the same score, and the words have changed over time. Here is where 56 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.
When is 56 part of an intellectual disability?
A score of 56 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.
Before you trust a 56
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 56 means on our test
The Assessivo test moves in steps of about 2.5 points, so it can't give exactly 56: the nearest results are 55 (0 correct) and 58 (1 correct). Every question has four options, so someone guessing every answer at random averages nine correct, a score of 78. Pure guessing gets nothing right only about once in 31,463 attempts, so a cat walking across the keyboard would expect to do better. A result this low almost always means the timer ran out or the answers never reached us.
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 56?
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 4 months |
| 8 | 4 years 6 months |
| 10 | 5 years 7 months |
| 12 | 6 years 9 months |
| 14 | 7 years 10 months |
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 56 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 56?
Line up 100 people of the same age and about 1 would score 56 or lower; the orange dot marks the place. In a school of 1,000 pupils, you would expect about 2 at or below this level.
The bar shows the likely range on a professional test, about five points either way: 51 to 61, from the 0.05th to the 0.47th percentile.
How 56 compares with nearby scores
| IQ | Percentile | Classic label | Score this low or lower |
|---|---|---|---|
| 51 | 0.05th | Extremely low | 1 in 1,838 |
| 56 | 0.17th | Extremely low | 1 in 596 |
| 61 | 0.47th | Extremely low | 1 in 215 |
| 66 | 1st | Extremely low | 1 in 85 |
Questions about an IQ of 56
What percentile is an IQ of 56?
An IQ of 56 is at about the 0.17th percentile: it is higher than about 0.17% of people of the same age, and roughly 1 person in 596 scores this low or lower.
Is 56 a low IQ?
Yes. 56 is 44 points, or 2.93 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 56 is best read as roughly 51 to 61.
Is 56 IQ an intellectual disability?
Not on its own. 56 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 56?
Mental age is an idea from the earliest tests for children. By the old formula, a 10-year-old scoring 56 would perform like a typical child of about 5 years 7 months. For adults it has no meaning: modern IQ tests compare adults with other adults, and an adult who scores 56 is not like a child.
Can someone with an IQ of 56 live independently?
Often, yes. The World Health Organization's ICD-11 says that people in the mild range, about 55 to 70, can generally achieve relatively independent living and employment as adults, although they may need appropriate support. Everyday skills and the right help matter far more than the score itself.
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.
An IQ test arrives at a score like 56 by combining several kinds of task. Learn more about abstract reasoning, spatial reasoning, verbal reasoning, processing speed and fluid vs crystallized intelligence, 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 56, 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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