How to Calculate the Percentile of a Value

A calculator can help you figure percentiles.

Percentiles represent the number of values that a specific value is equal to or greater than. Percentiles are often used in standardized tests to represent how well a student did compared to the rest of the test takers, rather than the percentage of questions a student got correct. The higher the percentile, the better the value. For example, someone scoring in the 90th percentile did as well or better than 90 percent of the the people, while someone in the 30th percentile only did as well or better than 30 percent of the people.

Instructions

1. Count the number of scores that are below the given value. For example, if you scored 740 on a test, count the number of test scores below 740.

2. Count the number of scores equal to the given score and multiply the result by 0.5. You multiply by 0.5 because a score equal to the given value is neither higher nor lower, so it is counted as half a score, similar to the way a tie is counted as 0.5 when calculating a win-loss percentage. For this example, if 40 other test takers got a 740, multiply 40 by 0.5 to get 20.

3. Add the number of scores below the given value plus half the scores equal to the given value. In this example, if 500 scores are below 740, add 500 plus 20 to get 520.

4. Divide the result by the total number of values. In this example, if there are 600 total values, divide 520 by 600 to get 0.87.

5. Multiply the result by 100 to convert to a percentile. In this example, multiply 0.8667 by 100 to find that a value of 740 is in the 87th percentile.

References

• Regents Prep: Percentiles
• Maths.com: Percentiles