What Is an IQ Test & How Is It Scored?

An IQ (Intelligence Quotient) test is a standardised assessment designed to measure cognitive abilities such as logical reasoning, pattern recognition, spatial awareness, verbal comprehension, and working memory. The average score is 100, and most people score between 85 and 115.

How Are IQ Scores Calculated?

Modern IQ tests use a statistical method called the deviation IQ. Your raw score is compared to the scores of a large reference group of the same age. The results follow a normal distribution (bell curve):

• The mean (average) is set at 100
• The standard deviation is 15 points
• 68% of people score between 85 and 115
• 95% of people score between 70 and 130
• 99.7% of people score between 55 and 145

IQ Score Ranges

What Do IQ Tests Measure?

IQ tests typically assess several areas of cognitive function:

• Logical reasoning — identifying patterns, sequences, and logical rules
• Spatial awareness — mentally rotating shapes, understanding 3D objects from 2D images
• Verbal comprehension — vocabulary, analogies, and reading comprehension
• Working memory — holding and manipulating information in your mind
• Processing speed — how quickly you can take in and use information
• Numerical reasoning — number sequences, basic arithmetic, and mathematical logic

Can You Improve Your IQ Score?

While your baseline cognitive ability is largely stable over your lifetime, there are ways to optimise your performance:

• Practice — familiarity with test formats genuinely improves scores
• Education — continued learning expands vocabulary, reasoning skills, and general knowledge
• Sleep — adequate sleep (7-9 hours) significantly improves cognitive performance
• Exercise — regular physical activity increases blood flow to the brain and promotes neuroplasticity
• Brain training — puzzles, strategy games, and cognitive exercises can sharpen specific skills
• Nutrition — a balanced diet rich in omega-3 fatty acids, antioxidants, and vitamins supports brain health
• Manage stress — chronic stress impairs memory and cognitive function

Types of IQ Tests

Several well-known IQ tests are used worldwide:

• Wechsler Adult Intelligence Scale (WAIS) — the most widely used clinical IQ test for adults
• Stanford-Binet Intelligence Scales — one of the oldest, covering ages 2 to 85+
• Raven's Progressive Matrices — a non-verbal test focusing on pattern recognition
• Cattell Culture Fair Intelligence Test — designed to minimise cultural and language bias

Frequently Asked Questions

What is the average IQ score?

The average IQ score is 100 by definition. Most people (about 68%) score between 85 and 115. A score of 100 means you performed exactly at the average level compared to others of the same age group.

Does IQ change with age?

Fluid intelligence (the ability to solve novel problems) tends to peak in your mid-20s and gradually decline. Crystallised intelligence (accumulated knowledge and vocabulary) continues to increase well into your 60s and 70s. Overall IQ tends to remain fairly stable throughout adulthood.

Are online IQ tests accurate?

Online IQ tests provide an estimate of your cognitive ability but are not as accurate as professionally administered clinical tests. They are useful for practice, self-assessment, and entertainment. For an official IQ score, you would need testing by a qualified psychologist.