Convert a 10-point CGPA to a percentage and back, with CBSE's 9.5 method or the formula your university publishes.
The right formula is the one your board or university publishes. Use the official conversion on your marksheet, transcript or ordinance whenever one is given.
A CGPA (cumulative grade point average) sums up your results on a points scale, usually out of 10 in India. Many admission forms, scholarship portals and job applications still ask for a percentage, and they rarely say how to get one. There is no single national formula. Each board or university decides how its grade points map to marks, so the same 8.6 can mean 81.7% under one rule and 78.5% under another. This converter shows the result for the most common methods and lets you type your own institution's formula.
CBSE's circular No. 24 of 2010, issued for its Class IX and X grading scheme, states that the overall indicative percentage of marks is 9.5 x CGPA, and that a subject's indicative percentage is 9.5 x the grade point in that subject. So a CBSE CGPA of 8.6 is 8.6 x 9.5 = 81.7%. Going the other way, 76% is 76 / 9.5 = 8.0. Because the top CGPA is 10, the highest percentage this method can give is 95%, which is why the tool warns you if you ask for the CGPA of, say, 97%. CBSE called this figure indicative, so treat it as an estimate of your marks, not an exact score.
The same circular describes the CGPA itself as the average of the grade points in all subjects, leaving out the additional sixth subject. If you want to rebuild your CGPA from a grade card, add the grade points of your five main subjects and divide by five, then multiply by 9.5 for the indicative percentage.
Universities publish their own rules, often in an ordinance or on the back of the grade card. Some use (CGPA - 0.75) x 10, under which 8.6 becomes 78.5%. Some simply multiply by 10, giving 86%. Others use a table of grade bands rather than one formula, and in that case no calculator can stand in for the table. With the custom option you can enter any rule of the form (CGPA - a) x b: for CBSE, a is 0 and b is 9.5; for the second example above, a is 0.75 and b is 10.
Take a CGPA of 7.2. CBSE's method gives 7.2 x 9.5 = 68.4%. The (CGPA - 0.75) x 10 rule gives 6.45 x 10 = 64.5%. Plain x 10 gives 72%. A form that asks for "at least 65%" could accept or reject you depending on which rule applies, which is exactly why you should quote your own institution's formula and keep a copy of the page where it is written.