Intelligence Quotient (IQ) Calculator
Use this calculator to determine an approximate Intelligence Quotient based on the classic formula developed by Alfred Binet and Theodore Simon.
This is the age level at which an individual performs intellectually, typically determined by standardized tests.
This is the individual's actual biological age.
Understanding the Intelligence Quotient (IQ)
The Intelligence Quotient, or IQ, is a score derived from a set of standardized tests designed to assess human intelligence. The concept of IQ was first introduced in the early 20th century and has evolved significantly over time. This calculator uses the original, classic formula for IQ, which is particularly relevant for understanding its historical development and application in children.
The Classic IQ Formula
The original IQ formula, popularized by psychologists Alfred Binet and later Lewis Terman (who adapted Binet's scale into the Stanford-Binet Intelligence Scales), is straightforward:
IQ = (Mental Age / Chronological Age) × 100
- Mental Age (MA): This refers to the intellectual level at which an individual is functioning. For example, if a 10-year-old child performs on an intelligence test at the same level as an average 12-year-old, their mental age would be 12. Mental age is determined by performance on standardized tests, where a score corresponds to the average performance of individuals at a particular chronological age.
- Chronological Age (CA): This is simply the individual's actual biological age in years.
How It Works: An Example
Let's say a child is 8 years old (Chronological Age = 8) and takes an intelligence test. Their performance on the test indicates that they are performing at the intellectual level of an average 10-year-old (Mental Age = 10).
Using the formula:
IQ = (10 / 8) × 100
IQ = 1.25 × 100
IQ = 125
In this scenario, the child's calculated IQ would be 125, suggesting above-average intellectual ability for their age group.
Limitations of the Classic Formula
While foundational, the classic IQ formula has significant limitations, especially when applied to adults:
- Mental Age Plateau: Intellectual development, as measured by these tests, tends to plateau in adulthood. An adult's "mental age" doesn't continue to increase indefinitely. If a 40-year-old and a 20-year-old both perform at a "mental age" of 20, the formula would suggest the 40-year-old has a lower IQ, which isn't an accurate reflection of adult intelligence.
- Not a Universal Measure: IQ tests primarily measure certain cognitive abilities (e.g., logical reasoning, verbal comprehension, spatial reasoning) and do not encompass all forms of intelligence, such as emotional intelligence, creativity, or practical wisdom.
Due to these limitations, modern IQ tests, particularly for adults, use a "deviation IQ" method. This method compares an individual's score to the average score of people in their own age group, with a mean IQ of 100 and a standard deviation of 15. This calculator, however, strictly adheres to the historical (Mental Age / Chronological Age) * 100 formula for educational purposes.
Using This Calculator
To use this calculator, simply input the Mental Age and Chronological Age in years. The Mental Age would typically be derived from a standardized intelligence test. The calculator will then apply the classic formula to provide an approximate IQ score. Remember, this tool is for illustrative purposes based on a historical model and should not be used for professional psychological assessment.