Multiply your Internal Assessment percentage by its weight, multiply your external exam papers’ average percentage by the remaining weight, add the two, and divide by 100 for a weighted composite percentage.
IB Biology SL Grade Calculator
Weighted composite score for IB Biology Standard Level, from your Internal Assessment and external exam paper scores.
Calculating an IB Biology SL Weighted Composite Score
IB Biology Standard Level combines an Internal Assessment (IA) — a student-led investigation — with external exam papers into a final 1–7 grade, with grade boundaries set only after each exam session. This calculator computes your own weighted composite percentage from your IA and exam scores for comparison against your teacher’s or IB’s guidance. It covers searches like IB Biology SL grade calculator, IB Bio SL composite score, and IB Biology grade boundaries.
How the IB Biology SL Grade Calculator Works
Formula
Weighted composite = (IA% × IA weight + External exam average% × (100 − IA weight)) ÷ 100
Worked Example
IA score 20%, IA weight 20%, external exam average 65%: Composite = (20 × 20 + 65 × 80) ÷ 100 = (400 + 5200) ÷ 100 = 56.0%.
Why the IA Weight Should Be Confirmed for Your Session
IB’s published weighting for Biology SL is commonly cited as around 20% IA and 80% external exams, but this weighting can be adjusted by the IB organization between sessions — confirm the current weighting with your teacher or the official IB subject guide for your exam session.
Frequently Asked Questions
Where do I find the official IA weighting for my exam session?
Check the official IB Biology subject guide or ask your IB coordinator or teacher for the current Internal Assessment weighting, since this can be updated between sessions.
Does this calculator predict my final 1–7 IB grade?
No — IB converts a composite score to the final 1–7 grade using boundaries set after each exam session, based on that session’s performance; these boundaries are not published in advance and vary by subject and session, so this tool only computes a weighted composite percentage.
How is the Internal Assessment scored?
The IA is scored by your teacher against IB’s published assessment criteria and may be subject to external moderation — check the official IB Biology subject guide for the current IA assessment criteria.
How many external exam papers does IB Biology SL include?
IB Biology SL includes multiple external exam papers, and this calculator’s “external exam papers” input expects your average percentage across all of them combined — check the official subject guide for the current paper structure.
Can I use this calculator for IB Biology Higher Level (HL) as well?
No — HL has a different assessment structure and its own official weighting between IA and external papers; use the specific weighting published for whichever level (SL or HL) you’re taking.
Why do IB grade boundaries change from session to session?
IB sets boundaries after each session specifically to account for that session’s overall difficulty and performance, keeping the 1–7 scale comparable in difficulty across different exam sessions and years.
Is the IA completed before or during the exam session?
The Internal Assessment is typically completed and submitted earlier in the course, well before the external exam papers are sat — check your school’s internal deadlines and the official IB subject guide for the current timeline.
