Percentile rank
A percentile rank tells you the percentage of people in a comparison group who scored at or below you. A percentile rank of 80 means you did as well as or better than 80 percent of the group. It shows where you stand relative to others, and it is not the same as the percentage of questions you got right.
In more detail
Percentile ranks appear on standardized tests such as the SAT, ACT and MCAT, in school screening tests and on growth charts. The comparison group matters. The same score has a different percentile rank in a national sample than among the students who actually took the test, and score reports usually say which group they use. Some textbooks count only scores below yours and others count scores at or below, so check the definition when numbers differ by a point or two.
Percentile ranks are not evenly spaced in raw points. Most scores cluster around the average, so a few extra raw points move you many ranks in the middle of the distribution and only a few ranks at the very top.
A percentile rank is a norm-referenced number. It says how you compare, not how much of the material you know. A student at the 90th percentile on an easy test can know less than a student at the 60th percentile on a hard one. That is the difference between a norm-referenced and a criterion-referenced result.
How to read a percentile rank
| Percentile rank | What it means | Out of 100 test takers |
|---|---|---|
| 25th | You did as well as or better than a quarter of the group | About 75 scored higher |
| 50th | You are at the median | About 50 scored higher |
| 75th | You did as well as or better than three quarters | About 25 scored higher |
| 90th | You did as well as or better than 90 percent | About 10 scored higher |
| 99th | You are in the top 1 percent | About 1 scored higher |
Example
Ten students score 55, 60, 65, 70, 70, 75, 80, 85, 90 and 95, and your score is 70. Three scores are below yours and two are equal to it. The middle formula, (3 + half of 2) divided by 10 times 100, gives a percentile rank of 40. Counting only lower scores gives 30, and counting scores at or below gives 50. Reports usually use one of the three, so check which.
How to use it
- 1
Find out which group the percentile compares you with: a national sample, everyone who took the test, or your class.
- 2
Turn your target into a score. If a program wants the 90th percentile, look up the score that reaches it in the official score tables.
- 3
Compare your practice test scores with the same table, not with the percentage of questions you got right.
- 4
Track your percentile over several practice tests, because a single test varies by a few points.
- 5
Use it for goals, not for study decisions. To decide what to study, look at the topics you missed.
How StudyPDF does this
StudyPDF does not rank you against other students. It tracks mastery per concept in your own course, so the number you see is about how much of the material you know, not where you sit in a crowd. For a test that reports percentiles, take a timed practice exam in the app, read the per-section report and match your score against the official score tables of that test. The breakdown lists your weakest concepts first, so you know what to drill.
See also
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Common questions
What does it mean to be in the 90th percentile?
It means you scored as well as or better than 90 percent of the comparison group, so about 10 percent scored higher. It does not mean you got 90 percent of the questions right.
What is the difference between percentile and percentage?
A percentage is the share of questions you answered correctly, such as 72 percent. A percentile rank is your position compared with others, such as the 72nd percentile. You can score 60 percent on a hard test and still be at the 90th percentile.