Pupils sitting GCSEs and A-levels next summer will receive fewer top grades than this year’s cohort, but will be given advance notice of some exam topics to help address learning lost as a result of the pandemic, Ofqual has announced.

The 2022 summer exams will be treated as “a transition year” with grade boundaries set midway between pre-pandemic levels in 2019 and 2021’s record results, after exams were cancelled for the second year running and replaced by teacher assessments.

Grades will then return to 2019 pre-pandemic levels for pupils sitting exams in 2023, who are now at the start of their GCSE and A-level courses, in the expectation that they will have avoided the worst of the Covid disruption.

The exams regulator is hoping the two-stage plan will succeed in reining in grade inflation and bring results back to normal levels, without triggering a sudden drop in results for pupils sitting their exams next summer.

Ofqual said more students will still get higher grades than before the pandemic, but with adjusted grade boundaries the proportion of pupils getting top A-level grades could drop by as much as 10 percentage points on last summer’s results, when almost 45% of all entries were awarded A or A* compared with 25% in 2019.

After a public consultation, the government and Ofqual confirmed a range of adaptations to next summer’s exams to make up for the disruption to learning, including a greater choice of topics in some GCSE exams like English literature and history.

Advance information about the focus of some exams will also be made available to schools in early February to help teachers and students make best use of the revision period in the final months before assessment, and support materials like formulae sheets for maths will be made available in exams.

Although the government has made plain its desire for exams to go ahead next year, Ofqual also published contingency plans for the use of teacher-assessed grades again in 2022 if exams have to be cancelled for a third year running because of Covid.

The education secretary, Nadhim Zahawi, said: “We’ve put fairness at the heart of our approach and listened to pupils, teachers and parents. The measures we’re putting in place will help reduce the impact of the significant disruption this group of young people have had to face – allowing them to move on to the next stage of their lives.

“We are committed to rigorous standards being fairly applied, and exams are the fairest way to assess students, which is why they will take place next year.”

Ofqual’s chief regulator, Dr Jo Saxton, added: “Our grading approach will recognise the disruption experienced by students taking exams in 2022. It will provide a safety net for those who might otherwise just miss out on a higher grade, while taking a step back to normal. Choice in some subjects and advance information to support revision are intended to provide support for all as we emerge from the pandemic.”

Dr Mary Bousted, the joint general secretary of the National Education Union (NEU), said the exams announcement had come too late and would not allay the anxiety or answer the questions many teachers have.

On exam adaptations, she said: “Only giving advanced information about the exams in time for revision will result in a ‘topic lottery’ where some students will have happened to have covered the topics on the exam in sufficient depth and others may well have not.”

Paul Whiteman, the general secretary of school leaders’ union NAHT, said: “Whatever decision was made about the approach to grading in 2022, it would be open to criticism by some. The most important thing is that this decision has been made and everyone involved now knows what to expect.”