IQ Percentile Calculator - Wechsler IQ to Rank Chart

An IQ percentile calculator is a cognitive assessment tool that converts an IQ score from the Wechsler, Stanford-Binet 5, or Cattell scale into the share of the reference population that scores at or below that value, paired with a Z-score and a Wechsler-aligned classification band.

• • Place a Wechsler IQ in a National Ranking: Convert a 122 IQ from a WAIS-IV into the 93rd percentile so admissions offices and giftedness programs read it on the same scale.
• • Check the Gifted Threshold: Confirm that an IQ of 130 on the Wechsler scale lands at the 97.7th percentile and clears the Very Superior band before a school placement decision.
• • Translate a Cattell or Older Stanford-Binet Score: Recompute an IQ of 100 or 115 on the SD 16 Cattell III or Stanford-Binet L-M / 4th edition scale so the percentile matches the report.
• • Show a Child the Meaning Behind a Test Score: Pair the raw IQ with the share of peers at or below it so a child sees what average or above average really means.

Most parents and adult test takers reach for an IQ percentile calculator right after the psychologist hands over the report, because the report usually states the IQ and the classification band but stops short of the exact share of the population at or below the score.

When the conversation moves from cognitive ranking to physical growth, the Baby Percentile Calculator applies the same normal distribution math to infant weight, length, and head circumference on the WHO infant growth chart.

The calculator standardizes the IQ score against the chosen test's mean and standard deviation, computes a Z-score, and looks up that Z-score on the standard normal cumulative distribution function to return a percentile between 0.1% and 99.9%.

• IQ: The IQ score from the test report, on a scale with a population mean of 100.
• mean: The population mean of the chosen IQ test, fixed at 100.
• sd: The standard deviation of the chosen test: 15 for Wechsler and Stanford-Binet 5; 16 for Cattell Culture Fair and the older Stanford-Binet editions.
• Z: The number of standard deviations the IQ sits from the mean; 0 is the median, +1 is one SD above.
• Phi(Z): The standard normal cumulative distribution function that turns a Z-score into a percentile.

When the scale is switched to the Cattell Culture Fair or an older Stanford-Binet, the same IQ produces a slightly different percentile because the standard deviation is 16 instead of 15, which spreads the same score across a wider population.

According to American Psychological Association, the Wechsler family of intelligence tests is standardized to a population mean of 100 and a standard deviation of 15, so about two thirds of test takers score between 85 and 115 and about 95% score between 70 and 130.

According to the Pearson WAIS-5 product page, the 2024 Wechsler revision keeps the same deviation IQ framework (mean 100, SD 15), which the Stanford-Binet 5 also adopted.

Because the calculator reports the Z-score alongside the percentile, the Z-Score Calculator is the natural next stop for users who want to see the same standard-score conversion for raw exam scores or any other normally distributed metric.

Four ideas drive every IQ percentile calculation, and understanding them turns a raw IQ into a number you can act on:

Keeping these ideas in mind prevents the most common mistakes: confusing a percentile with the share who score lower, switching between SD 15 and SD 16 mid-analysis, and reading a single IQ as a fixed label rather than a point estimate.

The Z-score concept is the bridge to pediatric growth percentiles, and the BMI Percentile Calculator for Children uses the same LMS method to convert a child's body mass index into a CDC percentile and Z-score.

Follow these five steps to turn a Wechsler, Stanford-Binet 5, or Cattell Culture Fair IQ into a national percentile and classification band:

1. 1 Open the Test Report: Have the psychologist's report in front of you so the calculator can use the exact IQ and test family.
2. 2 Enter the IQ Score: Type the IQ number from the report into the IQ field; a value between 40 and 160 covers the published range.
3. 3 Pick the Test Scale: Choose Wechsler (SD 15) for WAIS, WISC, WPPSI, and Stanford-Binet 5, or Cattell / Older Stanford-Binet (SD 16) for Cattell III, SB-LM, or SB4 reports.
4. 4 Read the Percentile, Z-Score, and Shares: Review the national percentile, Z-score, share at or below, and share above the IQ.
5. 5 Note the Classification Band: Read the Wechsler-aligned classification band (Average, High Average, Superior, Very Superior, Low Average, Borderline, or Very Low) to translate the percentile.

For example, a Wechsler IQ of 130 returns a 97.7 percentile, a Z-score of 2.00, and a Very Superior classification, the textbook reading for the Wechsler Gifted cutoff.

Using a Wechsler-aligned IQ percentile calculator gives families, educators, and clinicians several practical advantages over reading a raw IQ:

• • Same Numbers as the Clinical Report: Uses the same Wechsler mean 100, SD 15 and normal distribution as the psychologist's report.
• • Three Major IQ Scales in One Form: The result panel accepts a Wechsler, Stanford-Binet 5, or Cattell IQ, so the same form works for adult, child, and culture-fair reports.
• • Z-Score and Shares Included: The calculator reports the Z-score, the share at or below, and the share above, so a user can quote any of the four numbers without redoing the math.
• • Clear Classification Bands: A short Wechsler-aligned label (Average, High Average, Superior, Very Superior) turns the percentile into a phrase schools and giftedness programs recognize.
• • Quick Check on Test Interpretation: Recompute the percentile a minute after the test is scored, so a parent or teacher walks into a meeting with the same rank the psychologist will quote.

Most users keep the result open in a browser tab and reuse it through the school year, because the same IQ rarely changes between re-testings unless the test is repeated with practice or coaching.

For older students who already have a Wechsler score in hand, the SAT Score to Percentile Calculator applies the same normal-distribution idea to convert an SAT total and section scores into national percentiles for college admissions.

A few methodological and clinical factors change what the IQ percentile means and how the result should be read:

• • The calculator assumes the IQ is a single point estimate and does not propagate the standard error of measurement, so the 95% confidence interval is wider than the percentile shown on the result panel.
• • The percentile is computed against the test's full reference population and does not adjust for age, primary language, education, or disability status, so a low or high percentile in a non-typical test taker should be discussed with a clinician rather than acted on as a fixed label.

Headline percentiles also shift slowly across large populations, so a 97.7th today and a 97.5th next year are the same cognitive result and do not signal a meaningful change in ability.

According to the American Psychological Association schools and teaching resources on gifted and talented students, U.S. school giftedness programs typically use a Wechsler Full Scale IQ cutoff in the 125 to 130 range, which lands at the 95th to 98th percentile on the Wechsler (SD 15) scale.

The standard error of measurement discussion applies to pediatric growth too, and the Child Weight Percentile Calculator tracks the same kind of plus-or-minus range on a child's weight percentile up to 20 years.