Add each semester's GPA and credit hours to compute your overall, credit-weighted CGPA.
CGPA is credit-hour-weighted, not a plain average of semester GPAs: CGPA = Σ(GPA × Credit Hours) / Σ(Credit Hours). A semester with more credit hours counts for more.
This calculator shows an approximate percentage (CGPA × 25 on a 4.0 scale), the common rule of thumb several Pakistani universities' equivalence cells use. It's an approximation only — your own institution's official conversion table is authoritative for admissions/scholarship purposes.
Because credit hours differ by semester. A semester with 21 credit hours contributes more quality points to the overall CGPA than one with 15 credit hours, even at the same GPA — the per-semester contribution table shows this directly.