IQ calculator

IQcalculator test rules

• Taking IQcalculator test is just for fun. Although the IQcalculator test algorithm and the selected 200 questions are scientifically grounded, the calculated IQ score is just one of the ways to assess intelligence. The result of an IQ test should not be considered as the complete and sole measure of intelligence.
• No IQ test results are stored and test takers always stay anonymous. The test takers willing to store their IQ test result may opt for signing to the leaderboard by adding any anonymous nick.
• Test takers are not allowed to check test answers online or use support from other people or AI tools.
• Each IQ test may be taken only once, and may be retaken after minimum 6 months.

Time needed to take a test

Test takers should plan for an appropriate amount of time to complete the test. Since each test contains 200 questions, allowing 30 seconds for each answer means more than 1.5 hours. More difficult tests require more in-depth consideration of the questions and will require increasingly more time.

What is IQ?

IQ stands for Intelligence Quotient.

History of IQ

IQ has been originally created as a score that aims to measure a person's intellectual abilities compared to others of the same age.

Historically IQ was calculated using this formula:

IQ = (Mental Age ÷ Chronological Age) × 100

For example, if a 10-year-old child performed like an average 12-year-old, their IQ was:

(12 ÷ 10) × 100 = 120

Modern IQ

Modern IQ is no longer a quotient. Modern IQ tests use standardized scoring based on a large population sample. The scores are adjusted so that the average is always 100.

IQ is calculated using standardized scores based on population norms.

Scores follow a normal distribution with a mean of 100 and a standard deviation of 15. An average IQ score is set at 100. Most people score between 85 and 115. Scores above or below this range can indicate higher or lower than average intelligence, respectively.

What Does IQ Measure?

IQ tests usually assess:

• Logical reasoning
• Problem-solving skills
• Mathematical ability
• Memory
• Language understanding

IQ is just one way to understand intelligence and doesn’t measure creativity, emotional intelligence, or practical skills.

Types of modern IQ Tests

IQ can be assessed at any age:

• Children: WISC (Wechsler Intelligence Scale for Children)
• Preschoolers: WPPSI (Wechsler Preschool and Primary Scale of Intelligence)
• Adults: WAIS (Wechsler Adult Intelligence Scale)

Tests are tailored to the age group, and scores reflect performance relative to peers of the same age.

Other IQ tests include:

• Raven’s Progressive Matrices
• Stanford-Binet Intelligence Scales
• Cattell Culture Fair Intelligence Test

How this IQcalculator calculates IQ?

Persons taking the IQcalculator tests answer 200 questions. The IQcalculator's questions cover general knowledge and areas such as logical reasoning, verbal skills, math, patterns, and some others. Therefore IQcalculator compares intelligence in these covered areas.

IQcalculator uses a Z-score method. The Z-score method compares the current test score to the average performance of all reference test-takers from the norm group.

Z-score formula:

Z = (X − μ) / σ

where:

• X: The score of the current test-taker
• μ: Mean score of all reference test-takers from the norm group = 120
• σ: Standard deviation of the results of all reference test-takers from the norm group = 20

This Z-score is then converted to an IQ score using:

IQ = 100 + (Z × 15)

where:

• 100: The average IQ
• 15: The standard deviation of the IQ scale

Norm groups

A norm group is the sample population that was used to create the scoring standard for the test. Test-takers’ raw scores are compared to this group to calculate standardized scores like IQ.

Tests have different Norm gropus: Test 1 - Norm group - adults, Test 2 - Norm group - university students and graduates, Test 3 - Norm group - office workers, Test 4 - Norm group - managers, Test 5 - Norm group - scientists.

Each norm group contains people aged 18 to 65.

Difficulty of questions

The tests use questions at 5 levels of difficulty: (1) easy, (2) medium, (3) hard, (4) very hard, and (5) extremely hard.

Test 1 contains mostly easy questions and a small portion of medium, hard, and very hard questions. Subsequent tests contain an increasing portion of questions at a higher level of difficulty. Test 5 contains mainly questions of very hard and extremely hard difficulty levels.

Test questions are displayed from easiest to most difficult.

IQ score levels and examples for Test 1 - Norm group - adults

• Below 25 – Profound intellectual disability (requires full-time care)
• 25–39 – Severe intellectual disability (may understand basic instructions)
• 40–49 – Moderate intellectual disability (can perform simple tasks with guidance)
• 50–69 – Mild intellectual disability (can perform simple tasks)
• 70–79 – Borderline intellectual functioning (struggles academically, may hold simple jobs)
• 80–89 – Low average (some students, may find academics difficult)
• 90–99 – Average (basic learning and reasoning skills, many students)
• 100 – Standard average IQ (the statistical norm of adults aged 18-65)
• 101–109 – High average (functional learners, many students)
• 110–119 – Above average (university students, professionals)
• 120–129 – Superior (top students, engineers, teachers, team leaders)
• 130–139 – Gifted (university professors, scientists, managers)
• 140–149 – Highly gifted (researchers, mathematicians, inventors, top managers)
• 150–159 – Exceptionally gifted (rare students, the most talented leaders in reasoning based fields)
• 160+ – Genius level (geniuses)

IQ score levels for Tests 2 - 5

A score of 100 on IQ tests numbered 2 through 5 indicates an average score in the norm group. For example, a score of 100 on test 2 indicates an average IQ compared to university students and graduates. A score of 105 on test 3 indicates an IQ slightly higher than the average score achieved by office workers.