GradeA is only available for purchase through the Mac App Store, but there is a limited trial version available on my website http://www.dave256apps.com.
GradeA is an application for storing and computing grades and attendance records. Add custom categories (i.e., Homework, Quizzes, Exams, Labs) and add assessments for each category. Optionally drop a specified number of lowest scores from each category. Three different grading calculation methods: weighted average of categories, total points, and total points per category with weighted average of categories. Email reports to students (or parents for K-12) using Mail.app. Print individual reports to hand out to students. View/Edit grades by student or by assessment. Import names from a properly formatted CSV file. Export a CSV file with data. Undo support. User manual in the help menu. See http://www.dave256apps.com for more information.