The grading system in India

• The scale. Ten points, from 10 at the top to 0 for a fail. A few institutions use four or five points instead, and school boards run their own.
• The credits. Each subject carries a number that represents its teaching load. This is the weight in every average that follows.
• The average. Credit-weighted, at two levels: subjects into a semester, semesters into a degree.

Nothing else in the system matters as much as the second item, and it is the one students most often skip. What CGPA is works the arithmetic through in full.

Both the letters and the bands move between universities. Some use S instead of O at the top; some start A+ at 85 rather than 80; some add an E for a conditional pass. Use the point printed on your own grade card — the letters are local, the arithmetic is not.

Teaching time, not difficulty. The usual convention is one credit per weekly lecture hour across a semester, with laboratory and practical hours counted at half or a third of that. So a three-hour weekly theory course is worth three credits and a three-hour weekly lab is often worth one.

This has a consequence people find unfair and it is worth understanding rather than arguing with: a subject you struggled with all semester can be worth two credits, and one you found easy can be worth four. The weight comes from the syllabus, not from your experience of it.

Two reasons, and they are quite different.

The first is that bands differ by institution. A 79 is an A at one university and an A+ at another, purely because the boundary sits at 80 in one ordinance and 75 in the next. Nothing about the answer script changed.

The second is that some universities grade relatively rather than absolutely — the boundaries move with the cohort’s performance instead of being fixed in advance. How relative grading works covers what that does to your grade.

Alongside grading, most universities adopted a credit structure with a core, elective and audit split. The mechanics that matter for your grade card:

• Core courses carry credits and count fully.
• Electives carry credits and count fully, which is why an easy elective genuinely moves your CGPA.
• Audit and non-credit courses appear on the transcript with a grade and zero credits. They contribute nothing to either side of the division.
• Project and internship semesters often carry unusually heavy credit loads, which is where the gap between a plain average and a weighted one becomes large. SGPA to CGPA shows both figures.

Grade points are bands, and a band discards everything inside it. An 80 and an 89 both earn a 9. From the moment that grade is awarded, the nine-mark difference does not exist anywhere on your record and cannot be recovered — which is why CGPA to marks produces a representative figure rather than your actual score.

The practical effect is that two students with the same CGPA can be several percentage points apart on raw marks, and no conversion formula can distinguish them. It is also why converting a CGPA to a percentage is a convention rather than a calculation: the information the percentage would need was thrown away earlier.

At the end, because degree classes are still awarded in percentage terms at most universities — distinction, first class, second class. So the CGPA has to be converted, and which formula gets applied changes the class you are awarded. The CGPA to percentage formula sets the common ones side by side.