IQ 55: meaning, percentile and rarity
An IQ of 55 sits in the significantly below average range on the standard scale (mean 100, standard deviation 15). 0.13% of the reference population scores below this level, and 99.87% scores above it.
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- 0.13% of people score below IQ 55, and 99.87% score above it.
- Rarity
- About 1 in 740 people score IQ 55 or lower.
- Distance from the mean
- 45 points below the mean of 100 — about 3 standard deviations.
0.13% of people score below IQ 55, and 99.87% score above it.
What range does IQ 55 fall into?
An IQ of 55 sits in the significantly below average range.
Scores in this range are well below the mean. They should be read with caution: effort, test conditions, language and the limits of an online test can all pull a result down. A low score here is not a diagnosis — if it is a concern, a licensed psychologist can carry out a proper assessment.
How rare is IQ 55?
About 1 in 740 people score IQ 55 or lower.
Frequently asked questions
- Is an IQ of 55 a good score?
- An IQ of 55 sits in the significantly below average range, with about 0.13% of a normal population scoring below it. Whether that counts as good depends on what the score is used for — and no single online result should be treated as a definitive measure of ability.
- How rare is an IQ of 55?
- In a normal distribution, about 1 in 740 people score IQ 55 or lower.
- What percentile is an IQ of 55?
- 0.13% of the reference population scores below IQ 55. That is its percentile rank — a position on a scale from 0 to 100, not the share of questions answered correctly.
This page describes the theoretical normal distribution (mean 100, standard deviation 15) for educational purposes. It is not a clinical assessment or a diagnosis.