The Language Policy Secretariat (LPS) holds official examinations each year. These are announced in the Official Journal of the Government of Catalonia (DOGC), usually before the end of January. The exams usually take place in May or June and the registration period is at the start of the year. The LPS website contains all the information on these exams.
For more information about language certificates, go to: this link.
If you have studied in Catalonia or have any Catalan qualification, diploma or certificate issued by an official body outside Catalonia, see the LPS’ list of equivalent qualifications to the official Catalan certificates.
The Consortium for Language Standardisation (CPNL) runs officially recognised courses that allow students to obtain a certificate equivalent to that of the Secretariat for Language Policy. The courses lead to the attainment of each level of proficiency in the Common European Framework of Reference for Languages (CEFR): Basic A2, Elementary B1, Intermediate B2, Sufficiency C1 and Superior C2. In these courses, total assessment is the sum of the course assessment (and therefore completion of the tasks proposed by the teacher) plus the final mark for the proficiency test.
If you live outside Catalonia you can find where and when official examinations will be held on the website of the Institut Ramon Llull (IRL). The examinations can be sat by anyone of any nationality who is aged fourteen or over on the date of the test, and who wants an official accreditation of their knowledge of the Catalan language without having studied an official course.