The School is affiliated to the Council for Indian School Certificate Examinations. (CISCE). Students are prepared academically for the Indian Certificate for Secondary Education (ICSE) examination (Class 10), conducted by the Council.

Since 1995, the School has also been sending up Class 12 students for the Indian School Certificate Examination (ISC) in Science, Commerce and Humanities streams.  Science students can opt for Biology, Mathematics, or Computer Science as their elective subjects. Commerce Students can opt for Mathematics, Computer Science or Psychology. Humanities students can opt for Political Science, Computer Science or Psychology.

Students can pursue their careers in Medicine, Engineering, Chartered Accountancy, Law, Fashion Designing, Journalism, Department of Hospitality and Civil Defence Services to name a few.

Clarence High School has been able to obtain 100% results for a number of years and is very often the alma mater of the topper of the ISC Exams in South India.

NIOS – National Institute of Open Schooling , was set up in the year 1989 by the Ministry of Human Resource Development, Government of India as an autonomous organization.

The Rationale behind starting NIOS at Clarence High School in the year 2017, was to provide educational opportunities to students who wish to study further and qualify for a better tomorrow, students who for one or the other reason could not continue their education .It greatly opens avenues to students who would like to pursue careers in sports, art and Music to name a few.

Clarence High School is now an accredited Study Centre and Examination Centre for NIOS. Science and Non Science alternatives are offered to students who wish to pursue this curriculum.

It is offered through two modes : Weekly Classes ( MON – FRI, 3:15pm to 5:30 pm)   and  weekend classes ( Saturday, 9:00am to 12:30pm)