— IQ score explained

IQ of 78 — meaning, percentile & profile

An IQ of 78 is below the average range. IQ is one dimension of cognition and does not fully capture potential.

What does IQ 78 mean in practice?

An IQ of 78 means your raw performance on a standardised IQ test places you at the 7th percentile of the general adult population — lower than 93% of people. Many people at this level succeed across a wide variety of careers and life domains with the right conditions and strategies.

IQ 78 and the normal distribution

IQ is defined with a mean of 100 and a standard deviation of 15. An IQ of 78 is 1.47 standard deviations below the mean. The normal distribution tells us that:

• About 68% of people score between 85 and 115
• About 95% of people score between 70 and 130
• About 99.7% of people score between 55 and 145
• An IQ of 78 is higher than 7% of the adult population

IQ 78 and career outcomes

Career success depends on far more than IQ — motivation, perseverance, social skills, practical reasoning, and domain knowledge are all equally or more important than the IQ number for most real-world outcomes. Many people with IQs in this range lead highly successful and fulfilling careers.

Comparing IQ 78 to common benchmarks

How to accurately measure your IQ

A reliable IQ test uses Item Response Theory (IRT) scoring, which adapts the scoring based on item difficulty parameters rather than simply counting correct answers. Core Brain uses IRT 3PL (three-parameter logistic) scoring — the same statistical framework used by the WAIS and Stanford-Binet — and returns your score with a 95% confidence interval so you know the measurement uncertainty.

Related IQ scores

• IQ 65 — Extremely low range, 1th percentile
• IQ 70 — Borderline range, 2th percentile
• IQ 75 — Borderline range, 5th percentile
• IQ 80 — Low average, 9th percentile
• IQ 85 — Low average, 16th percentile

Related reading

• Full IQ-to-percentile reference chart
• What is the average IQ?
• IQ test types compared
• Mensa IQ score requirement