Is 105 a Good IQ Score? Where Five Points Count Most

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What does an IQ of 105 actually mean?

IQ scores are standardised so that the population mean is 100 and the standard deviation is 15. A score of 105 is five points above the mean, or one third of a standard deviation. In classification terms it sits inside the Average band, which runs from 90 to 109 and contains roughly half of everyone.

So by label, you are average. By rank, you are ahead of nearly two thirds of the population. Those two descriptions feel contradictory and both are correct, which is a good illustration of why classification bands are blunt instruments near the middle of the scale.

The exact percentile for an IQ of 105

Using the standard normal distribution, an IQ of 105 maps to the 63.06th percentile:

In a class of 30, around eleven pupils would be expected to reach 105. In a 100-person office, about thirty-seven. You are in the upper portion of a very crowded middle.

Why five points counts for more here than anywhere else

This is the genuinely interesting thing about a score like 105, and it is almost never mentioned.

The bell curve is not evenly spread. Most people are bunched near the middle and very few are out at the edges, which means the same five points moves you a completely different distance in rank depending on where you start:

Moving from 100 to 105 puts you ahead of about 131 more people in every thousand. The identical five-point move from 135 to 140 overtakes six. The gap you are sitting in is the densest part of the entire distribution, which means small differences here separate far more people than large-sounding differences at the top.

That cuts both ways, and it is worth saying plainly. Five points below you, at 100, sits half the population. Five points above, at 110, the whole labour market opens up in the occupational data. This region of the scale is crowded, and being in it means the people immediately around you are numerous.

But 105 and 100 are not reliably different scores

Here is the tension, and resolving it properly matters more than picking a side.

The WAIS-IV has a test-retest reliability of about 0.96 for Full Scale IQ, which is excellent, and a standard error of measurement typically quoted at plus or minus 3 to 5 points. If you scored 105, your true ability most likely sits between 100 and 110. A clinical report would give you that interval rather than the bare number.

Which means the five-point difference described in the previous section, real as it is in rank terms, is not something a single test can resolve. Someone who scored 105 and someone who scored 100 on the same afternoon may well have identical underlying ability. The one who scored higher may simply have slept better.

Both facts are true at once and they are about different things. The percentile arithmetic describes what a genuine five-point difference in ability would mean. The measurement error describes how confident you can be that the five points you are looking at are genuine. The sensible conclusion is to read your score as “somewhere around the upper half of average” rather than as a precise position.

The compensation is that this is the most reliably measured region of the whole scale. Standardisation samples are densest near 100, so the norms rest on more data here than anywhere else and different tests agree closely. That is the opposite of the situation above 130, covered in our guide to an IQ of 140.

What an IQ of 105 means for work and study

Being straight about this is more useful than reassurance.

In Gottfredson's (1997) synthesis of the occupational research, IQ 110 is the level at which virtually every occupation remains accessible, and it is also roughly where people can learn substantially on their own from the standard university teaching format. At 105 you are a little below that line, which in practice means options narrow gradually rather than abruptly. Most professional work remains available; the most cognitively demanding and heavily filtered routes become harder rather than closed.

Two things keep that from being the whole story.

Group means hide enormous variation. A profession with a mean of 112 contains plenty of people at 100 and plenty at 125. The mean describes a distribution, not an entry requirement, and nobody checks.

Cognitive ability explains less than the folklore claims. The long-standing figure putting cognitive tests at the top of the list of predictors of job performance was revised downward in 2022, after Sackett and colleagues identified a systematic overcorrection in decades of meta-analyses. Their revised estimate puts cognitive ability at about 0.31, below structured interviews at 0.42. A correlation of 0.31 accounts for under ten percent of the variation in how people perform, which leaves the overwhelming majority to conscientiousness, accumulated skill, reliability and opportunity. That argument is set out in full in our guide to an IQ of 100.

Can you raise a score of 105?

Modestly, and the honest evidence is narrower than the industry selling you solutions would suggest.

The best-supported lever is education. Ritchie and Tucker-Drob (2018) meta-analysed the question using designs that exploit things like changes to school leaving ages, and estimated a gain of roughly 1 to 5 points per additional year of schooling, persisting rather than fading. That is a genuine causal effect and it is the one intervention with good evidence behind it.

Commercial brain training produces gains that are largely specific to the trained task and transfer poorly to general ability. Sleep, exercise and treating an underlying health problem can all lift your measured score, mostly by removing something that was suppressing it rather than by adding ability. The full picture is in our guide to improving your IQ.

What to keep in mind about an IQ of 105

A few things worth knowing so you can read your score accurately.

• Average by label, above average by rank. The band says Average because it covers 90 to 109 and holds half the population. Your position inside it is comfortably in the upper half.
• You are in the densest part of the curve. Small point differences separate large numbers of people here, which is why a five-point move means far more at 105 than the same move would at 135.
• Read it as a range. Your true ability is somewhere between about 100 and 110, and no single test can place you more precisely than that. The upside is that the norms here are the most densely anchored on the entire scale.
• It measures one thing, and predicts less than you have been told. On current estimates cognitive ability accounts for under ten percent of the variation in job performance. Conscientiousness, skill and circumstance sit in the remainder, and most of that remainder is more responsive to what you do.

The bottom line on IQ 105

An IQ of 105 is slightly above average, at the 63rd percentile, ahead of about 63 people in every 100. It sits inside the Average classification band, which is accurate as a label and misleading as a description, because that band holds half the population and you are in its upper half.

The thing worth taking away is about the shape of the curve rather than the number. You are in its densest region, where five points separates 131 people per thousand instead of the six it separates up at 135. Differences here matter more in rank than the same differences at the top, and simultaneously are too small for a single test to resolve confidently. Hold your score as a range from roughly 100 to 110, and remember it accounts for under a tenth of what determines how work actually goes.

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