In order to be eligible for KCET you have to fulfill below eligibility criteria

• You must have studied and passed from a recognised institution situated in Karnataka. The academic study from a state institute should be for a minimum period of 7 years, starting from 1st standard to 2nd PUC/12th standard as on July 1 of the exam year.

• You should have appeared/passed either SSLC/10th standard or 2nd PUC/12th standard exam from Karnataka.

To know complete eligibility criteri ayou can refer below link

KCET Eligibility Criteria 

If you want to take admission in private engineering colleges of Karnataka you can apper for COMEDK exam.

Good Luck!!