A percentage alone cannot tell you which letter grade belongs on a result. That depends on the grading boundaries used for that examination or course.
Custom Grade Boundaries matches your marks to thresholds you enter yourself. The starting labels and percentages are examples. They are not a grading policy for every school, board or university in Pakistan.
Build the boundary ladder from a real grading table
Each row needs a label and its minimum percentage. A row labelled A with a minimum of 80 means a score of 80% or higher can match that row, unless another entered grade has a higher qualifying threshold.
Rows are sorted from the highest minimum downwards. You do not need to enter them in order, but every threshold must be unique. Two labels at the same minimum would leave an ambiguous result, so the calculator rejects them.
Include a lowest band where the official table needs one. Without a qualifying lower threshold, a low score can correctly produce no matching entered grade.
What the example table does with 78 marks
The example boundaries are A at 80%, B at 70%, C at 60%, D at 50%, and Below D at zero. A score of 78 out of 100 matches B under that particular table.
At exactly 80 out of 100, the matched grade becomes A. Thresholds are inclusive. The tool uses the underlying percentage rather than assigning a grade from a rounded display.
The worksheet also shows whole marks needed for each threshold. If an A boundary is 80% on a 75 mark paper, 60 whole marks meet it.
Where a boundary calculator does not apply
Relative grading can depend on a class distribution or an instructor’s grading decision. A fixed percentage ladder cannot reproduce that process without an official fixed table to use.
Separate component pass rules also remain separate. Matching a course percentage to a label does not show that a laboratory, practical or final examination has been passed individually.
A grade label is not a grade point conversion
This tool returns a matching label from your own ladder. It does not turn that label into GPA or certify a grade on a transcript.
For Semester GPA, enter the grade point accepted by your institution. Keep the official grade table with your calculation so that a later reader can see exactly which thresholds produced the label.