The National Institute of Open Schooling has certain significant features in its evaluation system. One such feature is freedom to answer the questions in Public Examinations in any one of the scheduled regional languages, although the Question Papers supplied would generally be in English and Hindi/ available Regional mediums only. Intimation letters and Certificates have scanned photographs of the learners. The information about Examination Centres and result are made available on the NIOS website. NIOS has been doing innovations in the evaluation system to maintain its credibility and standards. The On Demand Examination System (ODES) at the Secondary and the Senior Secondary levels for the registered candidates is one such innovation.

The Public Examinations are held twice a year in the months of April-May and October-November on the dates fixed by the NIOS.

For fresh and unsuccessful candidates of previous examinations > 21st November to 20th December (Without late fee).

For candidates who have been unsuccessful in the preceding examination i.e. October Exams >1st December to 20th December (Without late fee).

For all learners > 21st December to 31st December (With late fee).

1st January to 10th January (With consolidated late fee).

For fresh and unsuccessful candidates of previous examinations > 21st May to 20th June (Without late fee).

For candidates who have been unsuccessful in the preceding examination i.e. April Exams. >1st June to 20th June (Without late fee).

For all candidates > 21st June to 30th June (With late fee) 1st July to 10th July (With consolidated late fee).