OCR MEI Maths UMS Converter

Note: since I created this converter, OCR have updated their own version on their website here to include all past papers. So this tool is now redundant, but I'll leave it online.

This calculator converts a raw mark to a scaled mark (UMS) which is graded out of 100. 80% UMS is needed for an A, 70% for a B, 60% for C ...
AS and A2 modules have equal weighting in your final grade.
For A* at A2 maths, you need 90% in C3 and C4, and an 80% average across all units.
For A* in A2 further maths, you need 90% in three A2 units (DE, FP2, FP3, S2+, D2+ and M2+) and an 80% average overall.
Coursework marks are not included in this calculator. So in coursework modules (e.g. C3), just enter your mark out of 72 in the paper. This is because the coursework grade boundaries stay the same every year.

Choose a year

January May/June

Choose an exam

Your score

Calculate UMS

Your result

Grade boundaries:

Full	A*	A	B	C	D	E	U
100%	90%	80%	70%	60%	50%	40%	< 40%

How it works

I took the grade boundaries from the OCR and MEI website PDFs and collated them. You can download this raw data here (JSON format grouped by year). The boundaries for 80%, 70%, 60%, 50% and 40% are listed here.
For most GCSE and A-level exams, including these, a graph of UMS-percentage against raw mark would be a straight line between the E grade and 100% UMS (unless 100% UMS would require more marks than 100% raw marks, in which case the gradient is decreased after 80% UMS so that it passes through 100% UMS when at 100% raw marks). This calculator uses interpolation/extrapolation to calculate the exact UMS using this concept. Occasionally it will be one mark away from the actual OCR calculation, but this is quite rare and for past-paper purposes, ±1% is fine.