Headteachers have welcomed changes to the new GCSE grading system that will ensure it is as "fair" as the previous set up.
It was recently announced that from 2017 grades would change from letters, A* to G, to numbers, 1 to 9, for English language, English literature and maths.
On Wednesday, exam regulator Ofqual confirmed that the grade 9 would be awarded to the top 20% of grades at 7 or above in each subject.
This will mean the grade 8 boundary will be equally spaced between grades 7 and 9.
Dr William Richardson, general secretary of the Headmasters' and Headmistresses' Conference (HMC,) said: "Ensuring that the new top grades at GCSE will be fairly awarded to pupils taking the full range of subjects next summer has been a complex problem.
"This solution is a good example of well-focused research and listening to school-based experts.
"It should mean that pupils can confidently expect the new grading to be as fair as the previous system across all subjects when it comes to awarding top marks."
He added that, as the boundary for grade 9 will be set above the old A* grade, this should encourage universities and employers to "avoid unnecessary additional pressure being placed on students as a result of the new structure".