Dear Colleagues,

Many schools worldwide offer both the Cambridge IGCSE and the IB Diploma Programme (IBDP), which often requires teachers to align or approximate grades between the two systems. As there is no official conversion provided by either Cambridge or the IB Organization, this note offers a practical and consistent approach based on the June 2025 Cambridge IGCSE Computer Science (0478) grade thresholds.

Step 1: Use Cambridge Thresholds (Paper 1 + Paper 2)

Convert student marks to percentages (out of 100), based on the official thresholds:

• A* ≈ 82%+
• A ≈ 67–81%
• B ≈ 51–66%
• C ≈ 36–50%
• D ≈ 31–35%
• E ≈ 27–30%
• F ≈ 23–26%
• G ≈ 19–22%

Step 2: Approximate Conversion to IB Grades

Based on commonly used school-level equivalences:

• A* → IB 7
• A → IB 6
• B → IB 5
• C → IB 4
• D → IB 3
• E → IB 2
• F/G → IB 1

Important Notes

• This conversion is not officially endorsed by Cambridge or the IB.
• It should be used for internal assessment, reporting, or prediction purposes only.
• Teachers should apply professional judgment, especially where assessments differ (e.g., missing programming content or varying exam difficulty).
• Consistency within the school is key and agree on one method and apply it uniformly.

Purpose

This guideline is intended to:

• Support teachers working across dual curricula
• Provide a fair and transparent grading approach
• Help align student performance expectations between IGCSE and IB

Kind regards,
Noureddine Tadjerout