How do the examiners calculate the overall percentage you got in all three of your exams?

[Kylie fan]

I got a really bad mark for my labs, and I was hoping that for these exams I would get at least a low 5 to compensate for that grade. I tried finding ways to calculate the total percentage (based on what I got for my mocks) but it was hopeless!

[TykeDragon]

Okay, this is how the overall mark is calculated in relation to labs and exams. Let's say we're talking Bio HL (which, if memory serves correctly because I don't actually do HL Biology, but either way as an example it would work:)

24% = Labs (48 marks)

20% = Paper 1 (40 marks)

36% = Paper 2 (72 marks)

20% = Paper 3 (40 marks)

Now, whether these numbers are completely right or not is irrelevant, but what is visible is that the numbers correlate as being worth exactly half in terms of overall percentage. This may not always be the case. eg 50/72 in paper 2 = 25% here. Language A1 is another 'easy' example in which one mark = 1% as it totals to 100 marks and everything is weighted the same as their marks. (The percentage is the weighting.)

The formula is to work out the PERCENTAGE in the exam (eg 20/40 = 50%) then get this percentage and then multiply it by the weighting in decimal form. eg x 0.2 if it is worth 20%. This gives you a number which is a chunk of the mark. You total all these up and it gives you your overall percentage. I'm going to ignore the fact that for the Bio HL example I've given you can just divide the marks by 2 for the percentage, and use the proper formula, so for example:

40/48 in labs = 83.3% (83.3 x 0.24) = 20

30/40 in P1 = 75%. (75 x 0.2) = 15

50/72 in P2 = 69.4%. (69.4 x 0.36) = 25

25/40 in P3 = 62.5%. (62.5 x 0.2) = 12.5

Now total up all of those components. The total you get is 72.5. This will be rounded by the IB to 73% overall as they always round in the candidate's favour (eg a grade boundary of 80.5 will round down to 80% whereas a candidate mark of 80.5 will be rounded to 81%. Obviously this is if it falls exactly to .5, so 0.3 won't be rounded up. )

Hope that's explained well! Just construct a formula similar to the one above and plug in your estimated marks to see how that would score you!