Grade Calculator

Formula: weighted percentage = Σ((score ÷ max score) × weight) ÷ Σ(weight) × 100, summed across every row with a valid, positive weight. Letter grade mapping: 90% and above = A, 80-89% = B, 70-79% = C, 60-69% = D, below 60% = F. Worked example 1: quizzes averaging 18/20 (90%) at weight 15, a project scoring 44/50 (88%) at weight 25, and a final scoring 81/100 (81%) at weight 60. Weighted sum: (0.90×15) + (0.88×25) + (0.81×60) = 13.5 + 22.0 + 48.6 = 84.1. Total weight: 15+25+60 = 100. Overall: 84.1%, a B letter grade. Worked example 2: a course with only two graded categories entered so far — participation scoring 10/10 (100%) at weight 10, and a midterm scoring 55/100 (55%) at weight 40 — with the final exam not yet entered. Weighted sum: (1.00×10) + (0.55×40) = 10 + 22 = 32. Total weight so far: 10+40 = 50. Current running grade: 32/50 × 100 = 64%, a D — useful for seeing where things stand before the remaining 50% of weight (the final) is graded. Edge cases the widget handles: a row with a max score of zero or blank is treated as contributing zero to the weighted sum rather than crashing on a division by zero, and the widget surfaces an inline hint whenever this happens so you know a row was skipped rather than silently ignored; a row with a blank or zero weight is excluded entirely from both the numerator and denominator, since it should not affect the calculation at all; if every row has zero or blank weight, the total weight is zero and the result displays as a dash rather than an undefined value. Practical tip: this calculator is equally useful for two different purposes — tallying your final grade after all assignments are graded, or checking your current standing partway through a course by entering only the categories graded so far (as in worked example 2). For the latter use case, remember that the "total weight" entered will be less than 100 if some categories are not yet graded, so the resulting percentage represents your grade on the portion of the course completed so far, not a prediction of your eventual final grade — you would need to estimate scores for remaining categories separately to project a final outcome. A useful variant of this second approach is scenario planning: add a row for each remaining, ungraded category with your target or expected score already filled in, alongside the categories already graded. The resulting overall percentage becomes a genuine projection rather than a snapshot of work completed so far, which is exactly how to answer questions like "what do I need on the final to keep a B in this class" — adjust the hypothetical final score up or down until the overall percentage crosses the threshold you are aiming for.