As of midnight, 396,990 undergraduates had places confirmed at UK universities, up 3% on last year, according to Ucas figures, and 352,590 have won a place on their first choice of course, up 2% on 2013.
For the first time this year, the total number of people going to university could top half a million, Ucas said.
In England alone, 292,650 students have been placed, up 2% on a year ago, along with 15,980 in Wales (up 5%), 11,110 in Northern Ireland (down 1%), and 27,910 in Scotland (up 4%).
The early figures show that 103,970 students are still awaiting results or decisions on university places, up five per cent on last year.
Ucas chief executive Mary Curnock Cook said: "Today's numbers are a reflection of the continuing strong demand for higher education. A combination of extra places available and the falling population of 18-year-olds means that students are in a good position to secure a place this year.
"Alongside the impressive numbers, this is also a story about individuals who have made a life-defining decision to invest in their personal growth and position themselves for a more fulfilling life and career."
As the A-level results are published, youngsters who have applied for university will be finding out whether they have met the grade requirements to take up their chosen course.
Demand for university is high again this year, with more than 659,000 people applying by the end of June - up 4% on last year.
Tens of thousands of students are expected to be searching for places through clearing, the process that matches those without a place to courses that still have openings.
Major reforms have meant that more places are available to would-be students, particularly those with good grades, than ever before.
Under a new system, there is now no limit on the numbers of students with an A and two B grades at A-level that universities can recruit, allowing them potentially to offer last-minute places to youngsters who do better than expected and meet this threshold. The Government has also made 30,000 more places available this year.
A number of leading institutions are expected to enter clearing, some of which do not usually take part in the annual process, to offer last-minute places to students with good grades above the cap.
Wendy Piatt, director general of the Russell Group, which represents 24 of the UK's top universities, said: "Some Russell Group universities may still have places available in some subjects for students who have done better than expected.
"There may also be places available for highly-qualified students who have narrowly missed out on their first choice. We encourage those students to get in touch with Ucas to see whether there may be places available to them."
Nick Foskett, vice-chancellor of Keele University, said the role of clearing is continuing to change.
"An increase of 30,000 extra spaces at universities for 2014/15 means more students are likely to be accepted into their first choice, even if their grades are slightly lower than universities requested. Many universities that have plans for growth will be using this year to expand their numbers, so will be keen to accept students that may have been rejected in previous years."
Universities Minister Greg Clark said: "Higher education is one of the most important sources of social mobility and I welcome the growth in the number of students from disadvantaged backgrounds.
"The lifelong benefits of higher education are significant. Graduates are much more likely to be employed than non-graduates. They also earn on average significantly more over their lifetime.
"This year we increased the number of higher education places to enable more students to access higher education and next year publicly-funded universities can choose to recruit as many students as are capable of benefiting from higher education. Lifting this cap on aspiration allows more young people to fulfil their ambition and their potential."
Nicola Dandridge, chief executive of vice-chancellors' group Universities UK, said: "Congratulations to all students receiving their results today and to those who have secured their place at university this autumn. Students should be proud of what they have achieved and those who have chosen to go to university can look forward to the life-changing opportunities that a university course offers.
"For the first time, numbers of students accepted to university or college to study a degree could top 500,000 by the end of the cycle."