Academic feedback has a direct impact on students' effort decisions and academic performance. However, the grades that are reported to students are often based on institutional or instructor preferences, with entities adopting a discrete or fine grading scale. In this study, we utilize a field experiment to assess how a Letter (LGS) or Numerical Grading System (NGS) impacts students' academic performance. The results indicate that the grading system utilized has no overall impact on students' performance. However, we do observe that there is a heterogeneous impact of the grading system across gender and students' pre-treatment performance.