With Homeschool Planet, you are free to use any grading scale you want with each individual assignment. When you set up grading for a class, you select all of the grading categories that you will use in the class (such as Homework, Tests, etc.) and give a weight for each of them. These weights are used only to calculate a total grade for the class (for example, 30% Homework and 70% Tests). Regardless of what values you enter there, you can still grade each individual assignment using your choice of a percentage, a letter grade, or a fraction (like 18 out of 20).