How Are IB Final Grades Calculated?

Demystifying the International Baccalaureate grading system. Learn how internal and external assessments are combined.

The IB Uses a 1–7 Scale, Not a Percentage

Unlike a typical American class, each IB subject is scored on a 1–7 point scale, with 7 being the highest. These per-subject scores are then added together across all six subjects, plus up to 3 additional "bonus points" from the Extended Essay and Theory of Knowledge, for a maximum possible Diploma score of 45 points.

Internal Assessment vs. External Assessment

Each subject's final 1–7 score is a combination of two parts:

• Internal Assessment (IA): Coursework graded by your own teacher, then externally moderated by the IB to ensure consistent standards across schools worldwide. This typically makes up 20–30% of the subject grade, depending on the course.
• External Assessment: The final exams, taken at the end of the course and graded entirely by external IB examiners with no involvement from your own teacher. This is usually 70–80% of the subject grade.

The exact split varies by subject — some courses (like Visual Arts) weigh internal coursework much more heavily, while most sciences and maths lean heavily on the final external exams.

The Extended Essay and TOK Bonus Points

Beyond the six subject scores, students write a 4,000-word Extended Essay and complete a Theory of Knowledge course, both graded on an A–E scale. Combined, these can add 0 to 3 extra points to the total Diploma score using a matrix that cross-references the two letter grades — meaning strong performance here can be the difference between 42 and 45 points.

What Score Do You Need to Get the Diploma?

To be awarded the full IB Diploma, a student generally needs at least 24 total points (out of 45), along with meeting minimum requirements in individual subjects and passing both the Extended Essay and TOK components — falling short in a couple of areas can prevent the Diploma even with a decent overall point total.

How This Compares to a Standard GPA

Because IB uses a totally different 1–45 scale, it doesn't translate directly to the familiar 4.0 GPA system — many US colleges convert IB scores using their own internal formulas, and some award college credit for scores of 5, 6, or 7 in Higher Level subjects. If you're also tracking a standard high school GPA alongside your IB coursework, our AP & IB Multiplier Calculator shows how IB and AP courses affect your weighted GPA specifically.