What Is IQ? A Complete Guide to Intelligence Quotient

You’ve probably heard someone say, “He’s got a genius IQ!” But what does that number actually mean? IQ, or Intelligence Quotient, is one of the most misunderstood concepts in psychology.

In this guide, we’ll go beyond the clichés to explore what IQ really measures, how it’s calculated, what it says (and doesn’t say) about your mind — and why it still matters in the 21st century.

What Exactly Is IQ?

IQ (Intelligence Quotient) is a score derived from standardized tests designed to assess a person’s reasoning ability, problem-solving skills, and intellectual potential.

The term was first coined in the early 1900s by psychologist William Stern and was later popularized through the Stanford-Binet Intelligence Scale.

In its simplest form, IQ = (Mental Age / Chronological Age) × 100. (Though today’s tests are far more sophisticated.)

What Do IQ Tests Measure?

Despite popular belief, IQ tests don’t measure how much you know — they assess how you think.

Modern IQ tests typically evaluate:

Important: Creativity, emotional intelligence, and practical skills are not measured by IQ tests.

IQ Score Ranges – What They Mean

IQ scores follow a bell curve, where the average is set at 100. Here's how scores are typically interpreted:

IQ Score Classification
130+ Very Superior (Gifted)
120–129 Superior
110–119 High Average
90–109 Average
80–89 Low Average
70–79 Borderline Impaired
Below 70 Extremely Low

About 68% of people score between 85 and 115.

Is IQ Inherited or Learned?

IQ is influenced by a mix of genetics and environment. Studies on twins and adopted children show that:

And yes, your IQ can change slightly over time, especially during childhood and adolescence.

The Limitations of IQ

IQ isn’t everything — and it certainly doesn’t define your worth. Critics of IQ testing point out several flaws:

In fact, someone with an average IQ but high emotional intelligence (EQ) may thrive better in relationships and leadership roles than a high-IQ individual with low empathy.

Why IQ Still Matters

Despite its flaws, IQ can be a useful predictor of certain life outcomes:

But remember: it’s a tool, not a prophecy. Motivation, curiosity, and resilience often outperform raw brainpower.

Famous IQs (Estimated)

Name Estimated IQ Known For
Albert Einstein 160+ Physics, Theory of Relativity
Marilyn vos Savant 228 Highest recorded IQ
Elon Musk 150–155 Innovation, Business
Stephen Hawking 160+ Theoretical Physics

These numbers are estimates and may not reflect actual test results.

Can You Improve Your IQ?

You can’t drastically change your core IQ — but you can sharpen the skills it measures:

Also, developing your EQ is often more impactful in real life than increasing your IQ score.

Final Thoughts: IQ Is a Starting Point, Not a Destination

IQ is a fascinating — and sometimes controversial — lens through which we view intelligence. But it’s just one piece of a much larger puzzle.

Your creativity, empathy, drive, and grit are equally important, if not more so.

So whether your IQ is 90, 120, or 150 — the question is: what will you do with it?