IGCSE results arrive on two different scales depending on the board and the subject, and this causes more confusion than the grading itself. Both scales are current; neither has replaced the other everywhere.
The letter scale
The older scale runs A star, A, B, C, D, E, F, G, with U for ungraded. A C is generally treated as a pass, and A star is the top.
This scale remains in use across much of the Cambridge international offering, which is what most students in Turkey sit.
The numeric scale
The newer scale runs from 9 down to 1, with 9 at the top. It was introduced to spread the top of the distribution: the old A star has been divided, and 9 marks a narrower band than A star did.
So a 9 is not the equivalent of an A star. It is above it. The rough alignment is 9 and 8 covering A star, 7 covering A, and 4 sitting near the old C.
Which pass is meant
Two different thresholds circulate. A standard pass is a C or a 4. A strong pass, which is what many sixth forms and universities ask for, is a B or a 5 and often higher in the subject relevant to the degree.
When a requirement says five passes including mathematics and English, the level intended is almost always the second one.
What determines the grade
Most subjects combine written papers, and some add coursework or a practical component. The weighting is published per subject and varies considerably.
Grade boundaries are set each session against that session's papers, which means last year's raw mark for a grade is not this year's. Practising against an old boundary table gives a falsely precise answer.
What matters for the next stage
IGCSE grades are read as evidence of readiness for A Level or IB rather than as a final qualification. The grade in the specific subject a student intends to continue carries far more weight than the overall spread.
This is why a strong grade in the intended subject and a modest one elsewhere is usually a better outcome than an even set of middling grades.