A 66 percent letter grade typically corresponds to a letter grade of "D" in many grading systems, indicating that the student has achieved a performance level that meets the minimum requirements for passing but is below average. In some institutions, it may also be considered a "C-" depending on the grading scale used. This grade suggests that the student has a basic understanding of the material but may need improvement in certain areas.
66% is a D grade and 99% is an A grade.
D.
66%
percent.
95.6 percent is an A.
A
A
Generally 90-100 % will give you letter grade A
Most scales have it at a B- Check to see which scale applies to you.
C
C
c