It's a system which turns a 'raw' grade into a mark out of 300. This mark is then turned into a percentage to gain the final grade. This is a guide to the process. http://store.aqa.org.uk/over/stat_pdf/UNIFORMMARKS-LEAFLET.PDF Once a mark out of 300 is calculated for UNIT 1 (120) and Unit 2 (180) The following boundaries are used A* =90% 270/300 A = 80% 240/300 B= 70% 210/300 C=60% 180/300 D = 50% 150/300 E = 40% 120/300 F=30% 90/300 G=20% 60/300 There are documents which give the full conversion for each unit. I cannot locate it right now. What it did help me with was deciding which papers to have remarked as it was clear which students had missed a grade by just a few UMS marks.