Go to Navigation > Grades.
Use the dropdown menu to choose Scales (View).
At the bottom of the page, click "Add a new scale".
- On the next page give your scale a name in the Name box that will identify it among other scales.
In the Scale box, create your scale. Each item in the scale should be separated by a comma. You can use as many options here as you require. You must order the comma separated elements in increasing order of value. For example, an A,B,C,D scale must be entered as D,C,B,A.
Write a detailed description in the Description box to remind you (or other teachers) of how the scale is to be used.
Save the changes. Once you've saved, you'll be able to select this scale when setting up your assignment.
These instructions were adapted from the moodle.org instructions for creating custom scales.