The ACT is divided into four sections: English, Reading, Mathematics, and Science Reasoning. The maximum sub-section score is 36, while sub scores, which are only given in English, Mathematics, and Reading, range from 1-18. The composite score is the average of all four sections. In addition, the person taking the test may receive a writing score ranging from 1 to 12. The writing score does not affect the composite score directly, but is averaged with the English score for an English/writing score.
The average score is around 20 to 21. Any composite score over 30 is considered to be in the 99th percentile. In the 2004-2005 testing cycle, 251 students nationwide received a perfect ACT composite score of 36, a lower number than perfect scores on the SAT, mostly because of the lesser number of ACT test takers.