I use percentages to map to letter grades.The percentages mirror the 4.0 scale, except that where a GPA difference of 1.0 corresponds to a full letter grade,I use a percentage difference of 10. The table below shows the conversion from numerical grades to letter grades.
Number → Letter Conversion | |
---|---|
Numerical Grade | Letter Grade |
≥ 97.5 | A+ |
≥ 92.5 | A |
≥ 90.0 | A- |
≥ 87.5 | B+ |
≥ 82.5 | B |
≥ 80.0 | B- |
≥ 77.5 | C+ |
≥ 72.5 | C |
≥ 70.0 | C- |
≥ 67.5 | D+ |
≥ 62.5 | D |
≥ 60.0 | D- |
< 60.0 | E |
Letter → Number Conversion | |
---|---|
Letter Grade | Numerical Grade |
A+ | 98.75 |
A | 95.00 |
A- | 91.25 |
B+ | 88.75 |
B | 85.00 |
B- | 81.25 |
C+ | 78.75 |
C | 75.00 |
C- | 71.25 |
D+ | 68.75 |
D | 65.00 |
D- | 61.25 |
E | 55.00 |
Why I don't round grades
It is my practice not to round the numerical grade before mapping to letter grades by the table. This can be a sore point, so let me explain. For example, I use ≥90.00 as the transition from a B+ to an A-. This means that if your numerical grade is 89.9, I map it to a B+ and not an A-. It can be heartbreaking to miss a grade boundary by -0.1, I know. But to round up, say, every numerical grade ≥89.50 to 90.00 and map that to an A-, means that the transition from B+ to A- is actually 89.50, not 90.00. And that would mean that a grade of 89.4 would miss a grade boundary by -0.1. (It would also mean that me announcing the grade boundary of 90.00 is not accurate.) No matter what policiy is followed, some could miss a grade boundary by a hair. Even though there may be some psychological difference between the two situations, I prefer to keep it straightforward by announcing the sharp grade boundary and then following it strictly. I find it helps keeps the process more objective, and does not allow room for subjective grade adjustments, which are almost always unfair.