A-level and GCSE students in England will get their teacher-assessed grades earlier in August to give them more time to appeal.
Gavin Williamson announced in January that exams would be scrapped this summer due to the COVID-19 pandemic.
Pupils will return to the classroom from 8 March as lockdown is eased, with the government on Tuesday announcing extra support to help children catch up on lost learning.
Now the education secretary has set out more details on how the revised assessment process will work for results this summer.
A-level students will get their results on 10 August, while GCSE pupils will get their grades on 12 August.
Pupils will be able to appeal their grades at no additional cost and will have the chance to sit exams in the autumn if they are still unhappy with their marks.
Teachers will be provided with optional assessment questions for students to answer in order to help them decide what grades should be awarded.
However, the assessments are not expected to take place under exam conditions.
Teachers will have the flexibility to choose how long students will have to complete the task and where it will be carried out.
They will be able to base their grades on a range of evidence, including mock exams, coursework, essays and in-class tests.
Grades will have to be submitted to exam boards by 18 June, with quality assurance checks then taking place.
Teachers will be given guidance on how to make judgments before the Easter holidays.
Those studying for vocational and technical qualifications will also get teacher-assessed grades rather than having to sit exams.
There was controversy last summer when an algorithm downgraded the results of thousands of students, before it was eventually scrapped.
This time round however, exams regulator Ofqual will not use an algorithm to standardise estimated grades if they appear to be more generous than they should be.
According to the Department for Education, schools and colleges will conduct numerous checks to ensure the estimates are as fair as possible, along with the exam boards.
“Young people have shown incredible resilience over the last year, continuing with their learning amidst unprecedented challenges while the country battles with this pandemic. Those efforts deserve to be fairly rewarded,” the education secretary said.
“That’s why we are providing the fairest possible system for those pupils, asking those who know them best – their teachers – to determine their grades, with our sole aim to make sure all young people can progress to the next stage of their education or career.”
Ofqual’s interim chief regulator Simon Lebus said: “The aim is to make it no harder overall for this year’s students to receive a particular grade than students in other years.”
Labour’s shadow education secretary Kate Green said the “delayed announcement of the replacement for exams has created needless stress for pupils, parents and teachers”.
“Gavin Williamson created chaos last summer and this cannot be allowed to happen again,” she said.
“The government must now set out the detail schools and colleges need to ensure every pupil receives fair grades which enable them to move onto the next stage of their education, training or employment.”
Paul Whiteman, general secretary of the school leaders’ union NAHT, said the arrangements “appear to chart a path which avoids the awful chaos of last year”.
He continued: “This set of decisions is, however, only the starting point. It is now down to the awarding bodies to provide the detail which schools and colleges need to implement the process.
“Although earlier results for students seeking to start university could be beneficial, cramming GCSE results into the same week will place unnecessary pressure on to the system.”
Mary Bousted, joint general secretary of the National Education Union, also gave a cautious welcome to the plans.
“However, there are still question marks over how it is expected that the extra work necessary to facilitate grading will be dealt with,” she said.
“Substantial time will need to be set aside for the initial assessments and gradings and then the internal school moderation processes.
“It may well be that extra staff need to be employed to release teachers for this important work.”