I use two different scales, depending upon the reporting period:

Letter Grade Percentage range
Weeks 1 - 15
Percentage Range
Final Semester Report Card
A 90.0% or higher 89.5% or higher
B 80.0 to 89.99% 79.5% to 89.49%
C 70.0 to 79.99% 69.5% to 79.49%
D 60.0 to 69.99% 59.5% to 69.49%
Fail Below 60.0% Below 59.5%

 

The brackets for the final report are somewhat lower to allow for various factors and are the only adjustments that I make on the grading scale.

On a point of history, in the past I have used other grading scales:
  • AP Econ used 8% brackets rathen than the 10% brackets shown above.
  • Computer repair used 80%=A, 70%=B, 62%=C, 55%=D. (This course was based on an industry standard exam that was a pass/fail test with 70% as passing.