How to Calculate Iq

by

Intelligence Quotient (IQ) Calculator

Method 1: Classical Ratio IQ

Used historically for children, comparing mental maturity to actual age.

Method 2: Standard Deviation IQ

Used for modern standardized tests (Wechsler/Mensa style).

function calculateRatioIQ() { var ma = parseFloat(document.getElementById('mentalAge').value); var ca = parseFloat(document.getElementById('chronologicalAge').value); var resultDiv = document.getElementById('ratioResult'); if (isNaN(ma) || isNaN(ca) || ca <= 0) { resultDiv.innerHTML = "Please enter valid numbers."; return; } var iq = (ma / ca) * 100; resultDiv.innerHTML = "Estimated Ratio IQ: " + Math.round(iq) + getClassification(iq); } function calculateDeviationIQ() { var raw = parseFloat(document.getElementById('rawScore').value); var mean = parseFloat(document.getElementById('testMean').value); var sd = parseFloat(document.getElementById('stdDev').value); var resultDiv = document.getElementById('deviationResult'); if (isNaN(raw) || isNaN(mean) || isNaN(sd) || sd = 130) label = " (Very Superior)"; else if (score >= 120) label = " (Superior)"; else if (score >= 110) label = " (High Average)"; else if (score >= 90) label = " (Average)"; else if (score >= 80) label = " (Low Average)"; else if (score >= 70) label = " (Borderline)"; else label = " (Extremely Low)"; return "Category: " + label + ""; }

How is IQ Calculated? Understanding the Formulas

Intelligence Quotient (IQ) is a total score derived from several standardized tests designed to assess human intelligence. Historically, the methods for calculating these scores have evolved from simple ratios to complex statistical distributions.

1. The Classical Ratio Formula

Developed by William Stern and refined by Lewis Terman for the Stanford-Binet Intelligence Scales, the original IQ formula was based on the concept of "Mental Age."

IQ = (Mental Age / Chronological Age) × 100

Example: If a 10-year-old child (Chronological Age) performs at the level of a 12-year-old (Mental Age) on a test, their IQ would be (12/10) × 100 = 120.

2. The Modern Deviation IQ

Modern tests like the WAIS (Wechsler Adult Intelligence Scale) or Mensa admission tests use a "Deviation IQ" method. This places an individual on a Bell Curve (Normal Distribution) relative to their peers.

  • Mean: Most modern tests set the average score at 100.
  • Standard Deviation (SD): Usually set at 15. This means about 68% of the population falls between an IQ of 85 and 115.

The formula for deviation IQ is: 100 + 15 × (z-score), where the z-score is how many standard deviations you are away from the mean.

IQ Score Classifications

IQ Range Classification
130 and above Very Superior (Gifted)
120 – 129 Superior
110 – 119 High Average
90 – 109 Average
80 – 89 Low Average
70 – 79 Borderline

Important Considerations

While calculating your IQ can be insightful, it is important to remember:

  • Standardization: Professional IQ tests are proctored and validated. Online tests are often just for entertainment.
  • Cultural Bias: Some critics argue that IQ tests can be culturally biased, favoring specific linguistic or educational backgrounds.
  • Multiple Intelligences: IQ primarily measures logical, mathematical, and linguistic reasoning. It may not capture emotional intelligence (EQ), creativity, or practical "street smarts."

Leave a Comment