IQ Score vs Percentile: Convert Any Score in Seconds

6 min read · IQ Tester

IQ score vs percentile comes down to this: the IQ score is a point on a scale where 100 is average, while the percentile tells you what share of your age group you scored higher than. So an IQ of 115 and the 84th percentile are two ways of saying the same thing.

The chart below converts any score from 70 to 145 in seconds. And if you'd like to know which skills are setting your percentile, IQ Tester finds your reasoning weak spots in about two minutes: Find my weak spots.

Score vs percentile in one sentence

Your IQ score says how far from average you are; your percentile rank says how many people you beat.

That's the whole difference. Here's the same idea in a few more ways:

• IQ score: a standard score. Average is 100, and 15 points is one standard step.
• Percentile: a rank from 1 to 99. The 75th percentile means you scored higher than about 75% of your comparison group.
• IQ vs percentile: you can always convert one into the other, as long as you know the scale (usually 15 points per step).

Is a percentile the same as a percentage?

No, and this trips up a lot of students. A percentage is how many questions you got right, like 80% on a quiz. A percentile is how you ranked against others. You could get 60% of the questions right and still be at the 90th percentile if the test was hard for everyone.

Conversion table from 70 to 145

Here's an IQ percentile table for a standard scale (average 100, standard deviation 15). Percentiles are rounded.

Labels vary between tests, but the percentiles come straight from the bell curve and are the same for any test using this scale.

Want the exact number? Use the quick method

If your score isn't in the table, here's how to convert IQ to percentile yourself:

1. Subtract 100 from your score.
2. Divide by 15. That's your z-score (how many steps from average).
3. Put that z-score into any free normal-distribution calculator, or a spreadsheet using =NORM.S.DIST(z, TRUE).
4. Multiply by 100. That's your percentile.

Example: 118. (118 minus 100) ÷ 15 = 1.2. The area below 1.2 is about 0.885, so you're at roughly the 88th percentile.

That's all an IQ score percentile calculator does behind the scenes.

How to read a percentile

So what does IQ percentile mean when you see it on a result?

• 50th: exactly average. Half above, half below.
• 75th: you did better than three-quarters of your group.
• 91st: better than about 9 in 10.
• 98th: better than 49 in 50. This is the usual gifted-program range. See is 130 IQ good for a 13 year old for more.
• 99.6th: about 1 in 260 score this high. We do the math in how rare is 140 IQ.

IQ percentile for teens

Percentiles for teens work the same way, because each age is compared only with itself. A 15 year old at the 84th percentile beat about 84% of 15 year olds, not 84% of adults.

Why percentiles bunch in the middle

Look at the table again. Going from 100 to 110 jumps you 25 percentile points. Going from 130 to 140 moves you less than 2.

That's the bell curve at work. Most people are crowded near the middle, so a few IQ points there pass a lot of people. Out in the tails, there are so few people that each extra point barely changes your rank.

What this means in practice

• Near the middle, small score changes look big in percentiles. A move from 97 to 104 takes you from about the 42nd to the 60th percentile, even though that's well within normal test wobble.
• At the top, big score changes look tiny in percentiles. 135 and 140 are both "99th-ish."
• So don't panic about percentile jumps. If your percentile swings a lot between two tests and you're near 100, it's probably just noise.

Common misreadings

Here are the mistakes we see most often with IQ standard scores and percentiles:

1. "98th percentile means I got 98% right." No. It means you ranked above 98% of people.
2. "The 50th percentile is a failing grade." No. It's exactly average.
3. "115 is 15% smarter than 100." No. IQ points aren't percentages of anything.
4. "My percentile is exact." No. Your IQ has a margin of error of a few points, so your percentile has one too. That's also why IQ scores don't have decimals.
5. "Different scales give the same percentile." Not always. A 140 on a scale with 24 points per step is only about the 95th percentile.

What your percentile means for practice

A percentile tells you where you stand. It doesn't tell you which skill to work on. Two people at the 75th percentile can have totally different profiles: one sharp on patterns but slow at math, another great with words but tangled by long logic chains.

And working that out alone is harder than it sounds. You'll remember the questions that felt hard, but not whether you lost them to memory, rushing, or a gap in the skill itself.

IQ Tester does that sorting for you. Answer 16 questions in about two minutes, get a reasoning tier, and see which of seven problems show up for you, like working memory, pattern spotting or rushing then freezing. Find my weak spots

Turning a percentile into a plan

• Pick your weakest area.
• Practise it for about 10 minutes a day.
• Use a matching trick: Chunk it for memory, Name the rule out loud for patterns, Estimate first for numbers.
• Retest after a few weeks and see if your percentile, and the skill, moved.

Know what's behind your percentile in two minutes

IQ score vs percentile is just two views of one result; what changes things is knowing what to practise next. IQ Tester gives you a reasoning tier and your weak spots after 16 quick questions, then one tip and a roughly 10-minute drill each day aimed at them, with a streak, a history and retests any time.

Find my weak spots

FAQ

What does IQ percentile mean?

It's the share of your comparison group, usually people your age, who scored lower than you. The 84th percentile means you scored higher than about 84 out of 100 people.

What percentile is a 120 IQ?

About the 91st percentile on the standard scale (average 100, standard deviation 15). That means roughly 9 out of 10 people scored lower.

How do I convert IQ to percentile?

Subtract 100, divide by 15 to get a z-score, then look up that z-score on a normal distribution table or calculator. The result, times 100, is your percentile.

Is a 98th percentile IQ gifted?

The 98th percentile matches an IQ of about 130, which is the most common gifted cut-off. Schools set their own rules, though, and many look at more than one test.

Is an IQ percentile calculator free and accurate?

Most free calculators just apply the bell curve math, which is accurate for the conversion. The weak point is usually the IQ score you put in, which may come from a short test with loose norms.