### The formula for calculating percentiles is given as:

**B / T * 100 = percentile**

For example, a perfect 20/20 on the Grade 3 Winter Benchmark in Vocabulary is represented by the 87th percentile in reporting because, in the norming sample, 87% of students scored below 20/20 on the Grade 3 Winter Benchmark in Vocabulary. Or, in other words, 13% of students in the norming sample scored 20/20 on that measure.

For most easyCBM test forms we calculate a percentile for every possible score (within reason…i.e., for oral/passage reading fluency, once we get to 99th percentile for a given raw score there is no need to keep calculating percentiles for higher scores) using that basic formula for students included in the norming sample. For more information on the norming process see https://help.easycbm.com/