IQ, also referred to as intelligence quotient, is used to measure a person's intelligence. When we come across the abbreviation 'IQ', a lot of questions pop up in our minds―What does it actually count? What are average scores?, etc. You'll get answers to such questions in this article. A score of around 100 is said to be an average.

Ways to Calculate IQ

Previously, the IQ score was a ratio of mental age (MA) to chronological age (CA) and then this ratio was multiplied by 100.

i.e., IQ = MA/CA*100
If your score is above 100, then it means that your mental age is more than your chronological age. These days, psychologists do not use the above method for calculating the IQ. They use the statistical method, which reflects a person's intelligence.


140 +Genius and above
120 to 140Very superior intelligence
110 to 119Superior intelligence
90 to 109Normal or average intelligence
80 to 89Dull
70 to 79Borderline deficiency
Under 70Definite feeble mindedness

Scores and Normal Distribution

The characteristics of normal distribution apply to IQ scores as well. 50% of scores range from 90 to 110, while 70% range from 85 to 115. 95% falls between 70 to 130, and 99.5% ranges from 60 to 140, forming a bell-shaped curve of normal distribution among the general population.

IQ and Mental Retardation

People who have an IQ below 70 are said to suffer from mental retardation, and almost 5% of people in any population have it. The severity of mental retardation is divided into four levels as given.

People whose score ranges from 50 to 70 are said to suffer from mild mental retardation. Almost 85% of people in this category suffer from mild retardation. 10% of people suffer from moderate mental retardation which ranges from 35 to 50. People with scores ranging from 20 to 35 are said to suffer from severe mental retardation and almost 4% of people fit in that category. Those whose score is below 20 suffer from profound mental retardation and around 1% fall under this category, wherein they are not able to function independently and are totally dependent on others. While the mild, moderate, and severe mentally retarded can be trained partially in activities of daily living or vocational training, the profoundly retarded have to be institutionalized.

IQ and Genius

People with scores above 140 are said to be genius, and only 1 person among 400 have this level. Individuals whose score ranges from 115 to 124 are said to be about average and mostly university students, while score of students pursuing their post graduation ranges from 125 to 134. The IQ range of intellectuals is from 135 to 144. Professors are the actual genius people and their IQ ranges from 145 to 154 while noble prize winners have an IQ range of 155 to 164. Extremely gifted individuals have an IQ of 165 to 200, while people whose IQ is above 200, are said to be super genius.

Most of us have a normal IQ score, but there are two extremes of which a few are super genius―having IQs of more than 150 while some at the other extreme have a very low IQ. Anybody―those at the extremes of the normal distribution curve of intelligence or those with average intelligence―may suffer from mental illnesses due to emotional or maladjustment problems. Hence, emotional intelligence or emotional quotient (EQ) is becoming more important than IQ for a successful life.