Students in England, Wales and Northern Ireland will receive their GCSE grades later today as they work towards sixth form, college or training.
The number of pupils in England achieving at least a grade 4 in maths and English GCSE is expected to fall this year, amid efforts to restore grading to similar levels to 2019, the year before the coronavirus pandemic.
But Ofqual says it has built protection into the grading process which should enable a pupil to get the grade they would have received before the pandemic, even if their quality of work is a little weaker this year.
Live updates on GCSE results day
Earlier this week an education expert said GCSE results day "will not be as enjoyable" as it was during the pandemic as around 300,000 fewer top grades could be awarded.
Professor Alan Smithers, director of the Centre for Education and Employment Research (CEER) at the University of Buckingham, said pupils and parents may be in for a "shock" as grading standards are restored, which could lead to a "record drop in top GCSE grades".
He suggested there could be about 300,000 fewer entries graded 7 or above (an A or A* grade) compared with 2022 if grading standards return to 2019 levels.
How do grades differ across the UK?
Students in England, Wales and Northern Ireland will get their results today, with grading different across the three countries.
In England GCSEs are graded using a numerical system from 9 to 1 rather than from A* to G - with 9 being the highest grade.
In general a grade 7 and above is roughly equivalent to an A and above, while a grade 4 is considered a "standard pass".
In Northern Ireland the Council for the Curriculum, Examinations & Assessment uses a nine-category grade scale A*-G, which includes a C*.
Wales retained the traditional eight-category grade scale A*-G.
In Northern Ireland and Wales exam regulators have said they do not expect to return to pre-pandemic grading levels until next year.
What support did students receive?
In England pupils were given formulae and equation sheets in GCSE maths, physics and combined science exams to acknowledge pandemic disruptions to learning.
GCSE students were also not expected to confront unfamiliar words in language exams.
Exam papers in the same subject were spaced out more in the GCSE timetable than they were prior to the pandemic to give students more time to revise.
Many students in Wales and Northern Ireland were given advance information about topics to expect in their exam papers, though pupils in England were not given the same support.
What were GCSE results like last year?
More than a quarter (26.3%) of UK GCSE entries were awarded top grades last year, compared with 28.9% in 2021 and 26.2% in 2020.
In 2019 - the year before the pandemic - around one in five (20.8%) entries in England, Wales and Northern Ireland were awarded a 7/A or above.
Number of top A level grades down on last year
The GCSE results come after A-level grades were released last week - with the proportion of top grades down on last year but still above pre-pandemic levels.
Some 73,000 fewer top A-level grades were awarded in England, Wales and Northern Ireland than last year as part of efforts to bring results back down to pre-pandemic levels, exam boards said.
But there were around 32,000 more top grades awarded than in 2019.