How a GPA is actually worked out
Each grade becomes a number, that number is multiplied by the credit hours of the course, and the total is divided by total credits. Credit weighting is the part people miss: a poor grade in a four-credit course affects the average twice as much as the same grade in a two-credit one.
Which is why a single bad mark in a major module hurts far more than several in small electives.
Weighted and unweighted differ, and schools disagree
Unweighted caps at 4.0. Weighted scales add extra points for honours, AP or IB courses, so a 4.0 becomes a 5.0 and totals above 4.0 are possible.
There is no single standard for how much extra, whether A- is 3.7 or 3.67, or how a pass grade is treated. Universities usually recalculate applicants on their own scale, which is why the number your school reports and the number an admissions office uses often differ.
Frequently asked questions
Why does one bad grade affect my GPA so much?
Credit hours. A four-credit course counts twice as heavily as a two-credit one, so a poor mark in a major module moves the average far more.
What is the difference between weighted and unweighted?
Unweighted caps at 4.0. Weighted adds points for harder courses, so totals above 4.0 are possible. Schools differ on how much they add.
Will a university use the GPA my school reports?
Often not — many recalculate on their own scale so applicants can be compared fairly. Your reported figure and theirs can differ.
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