Students across England, Wales and Northern Ireland are ending more than six weeks of waiting as they learn their A-level results.
More than a quarter of entries are expected to score a top grade.
The grades will help young people decide their next steps, be it university, work, or training.
Last year, 26.4% of UK entries were awarded an A or A* grade, the highest proportion for six years.
However, the total number of students accepted on to UK degree courses has fallen with 408,960 taking up places so far, down 1% on the same point last year, initial Ucas figures show.
Proportion of A-levels awarded an A or A* last year
Meanwhile, one in 12 (8.0%) entries scored an A* grade, down 0.3 percentage points on last year, according to statistics published by the Joint Council for Qualifications (JCQ).
Boys are expected to continue to outperform girls at the highest grades again this year, last summer 26.6% of boys’ entries awarded at least an A grade, compared to 26.2% for entries from their female classmates.
Ahead of A-level results day, grade boundaries for two of England’s biggest exam boards, Edexcel and OCR, were leaked.
The documents showed that students needed to score just over half marks in A-level maths to be rewarded with an A grade this summer.
Grade boundaries for Edexcel’s maths A-level show students who gained 165 out of a possible maximum of 300 marks (55%) will be awarded an A.
Separate documents show that those who took the OCR exam board’s A-level maths qualification will walk away with an A if they achieved 54% across all papers – a total of 161 out of 300.
Last year, 184 marks (61%) were needed for an A grade in Edexcel’s maths A-level, while for OCR’s qualification in the subject, the required mark was 197 (66%).
The leaked documents also give grade boundaries for other A-level qualifications offered by Edexcel and OCR – two of the biggest exam boards in England, and there are some differences between the two.
For example, 69% (208 out of 300) in an Edexcel English Literature A-level achieves an A grade, while students taking the subject with OCR require 177 marks out of 200 (89%).
Grade boundaries change each year in order to ensure that a similar proportion of students receive each grade, so that any differences in the difficulties of papers do not disadvantage different cohorts of students.
Practically all A-level courses have now been reformed.
This summer is the first time that grades for new specification A-level maths are being awarded to the vast majority of students.
For many students, receiving their A-level results will also bring confirmation of university places.
Latest UCAS figures show that as of the end of June, 638,030 people had applied to start degree courses this autumn, up 0.2% on the same point in 2018.
Among UK 18-year-olds applications are up one percent, the statistics show, with 275,520 applying by the June deadline.
Those without degree places, who want to go to university will be searching through Clearing, the annual process that matches students with courses that have availability.
Clearing is increasingly becoming a popular route for students to find a degree course, with leading universities among those to offer last-minute places through the system.
Number of degree courses at English university with availability for students living in England
A PA survey shows that as of Wednesday afternoon 103 universities in England alone had availability showing for at least 50% of their courses for potential students living in England.
The survey also shows that in total, across all English universities, there were around 21,660 courses with places available.
Other students may be eschewing university for a different route into the workplace.
Kirstie Donnelly managing director at City & Guilds Group said: “For too long now, technical and vocational education routes have been cast into the shadows, with young people across the UK shepherded down the traditional pathway through GCSEs, A-levels and on to university.
“While these qualifications may be the right path for many, they should not be seen as the only option to gain a successful career.
“At a time when the UK is plagued with growing skills gaps, it’s never been more important for our young people to harness the full range of different routes into employment available to them.”