Formulas you can check
Our calculators use basic percentage and weighted-average arithmetic. This page explains what the numbers mean, which assumptions apply, and how to report a problem.
Test and quiz percentages
Percentage = earned points ÷ possible points × 100. In wrong-answer mode, earned credit equals total questions minus wrong answers. Question mode assumes equal question values. Points mode supports decimal scores and unequal question values when you enter the summed earned and possible points.
Example: 20 questions − 3 wrong = 17 correct. Then 17 ÷ 20 × 100 = 85%.
Weighted course grades
Course contribution = category percentage × category weight ÷ 100. The course grade is the sum of those contributions when graded weights total 100%.
For partial course data, completed-work average = sum of contributions ÷ sum of graded weights × 100. Blank grades are excluded; an explicit zero is included. The tool reports the graded weight so a partial average is not mistaken for a final grade. Entered course weights above 100% are rejected.
Final exam scores
Let C be the current grade excluding the final, T the target grade, F the final exam score, and W the final’s course weight as a decimal.
Required exam score = [T − C × (1 − W)] ÷ W.
Predicted course grade = C × (1 − W) + F × W.
The model assumes the final is the only remaining ungraded component. At a 0% final weight, the exam cannot change the course grade. A required result over 100% exceeds a standard exam maximum.
For an independently published derivation, see RogerHub’s final-grade formula documentation. This reference does not imply affiliation or endorsement.
Rounding and letter grades
Calculations retain their internal numeric precision. Percentages are normally displayed to two decimal places. Required final scores are rounded upward to hundredths when needed so the displayed requirement does not fall below the target because of ordinary rounding.
Homepage letter grades use the unrounded result by default. Whole-number rounding for letters is an explicit option. The initial A–F thresholds are editable examples, not an official scale. Read the grading-scale guide.
Validation performed for this version
During development, automated JavaScript checks covered the 17/20 example, invalid totals, blank inputs, threshold rounding, extra credit, and reset behavior. Weighted-grade checks covered full and partial weights, blank versus zero scores, and totals over 100%. Final-grade checks covered required and predicted results, targets above the exam maximum, blank inputs, and 0% and 100% final weights.
These checks verify selected cases; they are not an independent certification. The calculator output remains an estimate based on the values and rules you enter.
What the tools do not apply automatically
Curves, dropped assignments, replacement exams, attendance requirements, minimum exam scores, and institution-specific GPA or eligibility rules are outside the basic models. Consult your course policy before interpreting a result as an official grade.
Privacy and corrections
The calculator scripts perform arithmetic in your browser and do not send your entered scores to a calculation server. They do not require student names or accounts. See the privacy policy for website and contact data.
To report a suspected error, email contact@gradingcalculator.pro with the tool name, example inputs, expected result, and result shown. Please omit student names and private records.