IB Grade Boundaries Explained: How Your Final Score Is Actually Calculated
Understanding IB grade boundaries gives you a strategic advantage most students don't have. Here's how the system really works.
What Are Grade Boundaries?
Grade boundaries are the minimum raw marks needed for each grade (1-7), set after each exam session based on paper difficulty and global student performance.
Typical Chemistry HL boundaries: 7 = 76%, 6 = 64%, 5 = 52%, 4 = 38%. But these shift every year.
How Your Score Is Calculated
- Raw marks from each paper
- Weighting applied (Paper 1: 20%, Paper 2: 40%, etc.)
- Grade boundaries applied to weighted total
- Final grade (1-7) assigned
Strategic Takeaways
- You don't need 90% for a 7 — boundaries typically fall at 70-80%
- Every mark counts equally — easy marks are worth the same as hard ones
- IA is your secret weapon — high IA scores give you exam buffers
- Know your gap — if you need 6 more marks for a 6, that's specific and fixable
Common Misconceptions
- The IB doesn't "curve" — boundaries are based on difficulty, not rank
- Boundaries shift 5-10 marks between sessions
- Different subjects require different percentages for the same grade