More than one in four A-levels are expected to be awarded at least an A grade this year, but pass rates are set to stall, it has been predicted.
One in four papers is expected to achieve an A grade, on a par with last year's results.
98% is expected to be the overall pass rate, but 50,000 fewer students have applied to university this year.
Daybreak's Tiffany Royce reports:
A 19-year-old student has said his exam successes show it is possible to be educated at home right up to A-level.
Hundreds of families across the UK every year choose to take their children out of school and teach them at home.
But but very few continue this past GCSEs into the traditional sixth-form stage.
Eli Ingle, from Sheffield, already has two A*s - in business studies and sociology - and is hoping for similar high standards when he gets his psychology result later today.
He said: "It's so wide-ranging and there's so many opportunities I feel I've got that I would never have got at school.
"I've expanded my social range and I have managed to do all these qualification.
"It shows that you don't necessarily have to have an organised school environment to do it, there are other routes out there that work just as well."
– Carl Gilleard, chief executive of the Association of Graduate Recruiters (AGR)
My advice for those school leavers considering clearing is to take a step back and consider their options fully - going to university to study for a degree may not be the right path for everyone, and students who are pressured into making a snap decision today may come to regret it.
With the further rise in tuition fees this year, students need to be sure that university is the right investment for them.
– Brian Lightman, general secretary of the Association of School and College Leaders
When you are talking about those sorts of high grades, A and two Bs, people scoring those sorts of grades - for those to be disheartened would be a tragedy and we must do everything we can to enable them to get their place.
Teenagers in England, Wales and Northern Ireland are waking up to their A-level results today, with many hoping that their grades will be good enough to secure a coveted university place.
Experts have predicted that the pass rate will stall this year, amid fresh attempts by the exams regulator to tackle grade inflation.
It has been suggested that around 8% of exams will achieve an A* and just over one in four exams will score at least an A - the same as in 2011.
It would be a "tragedy" if bright teenagers who just miss their grades and lose out on a university place are disheartened.
Everything must be done to ensure that these youngsters secure their spot, according to Brian Lightman, general secretary of the Association of School and College Leaders (ASCL).
He said his advice to students who find themselves without the grades they need would be "don't give up" and to look at the many other options available.
Concerns have already been raised that changes to university admissions will mean that able teenagers who are predicted to score two As and a B, but just fall short, struggle to find a university place this year.
- Students in England, Wales and Northern Ireland are due to receive their A-level results today.
- For many, the results will mean that their university places are assured, while others - who find their grades are lower than expected - will look for courses through the clearing process.
- Students heading to English universities this autumn will be the first to pay fees of up to £9,000 a year.
Universities should embrace the government's market reforms of higher education by competing with each other for undergraduates, David Willetts told the Guardian.
Elite universities such as Oxford and Cambridge should offer more places to students to ease the annual scramble for the most sought-after institutions, reports the Telegraph.