More than 28,000 teenagers have registered to receive their results online for the first time, said the exam board Edexcel, which is pioneering the new system.
The majority of Edexcel's students are still expected to find out their results at school because there are worries about some teenagers receiving bad news while on their own. Students able to log on to Results Plus will be able to see their exam grades and marks for individual units from 6am on results day. Exam boards AQA and OCR are developing technology to enable them to follow Edexcel's lead.
Chris Montacute, head of Wootton Bassett school in Wiltshire, said: "Some students are very nervous about coming into school to get their results and therefore receiving them at home would be much more reassuring. Many others will want to come to school anyway because they like the camaraderie and the chance to see their friends and share the news."
Mr Montacute, whose school piloted the internet-based service last year, said it gave teachers more information about their students' performance and helped them to plan lessons more effectively. Andrew Harland, chief executive of the Exam Officers' Association, said he expected that only a small proportion of schools would hand out PIN numbers. "The main Edexcel centres, the big sixth form colleges and secondaries, are the ones most likely to give them out," he said.
Mr Harland said that less than half the exams officers he had heard from were giving out PIN numbers. Of the 93 exams officers at a conference in Manchester, only one said her school was releasing them.
Mr Harland was concerned that teenagers would miss the happy atmosphere of results day and the relationship between schools and students could be undermined. He said: "Seeing students get their results is a fantastic experience for exams officers. There is a general consensus that this is just another thing being thrown at them."
Helen Finch, exams manager at Hugh Christie 11 to 18 technology college in Tonbridge, Kent, said her school was not giving out PIN numbers. She said: "There are concerns about children who are on the edge of getting particular grades where the results could decide whether they get into the university or the job they want.
"Teachers feel they need to be there to discuss things."
John Bangs, head of education at the National Union of Teachers, said he believed receiving results was better at home, as long as friends and family were there.
He said: "There are youngsters who like to celebrate with each other and feel nostalgia for what could be their last school visit. For those who have not done as well as they thought, that experience can feel like humiliation."