CPT stands for Curricular Practical Training. Designed for F-1 students who want to complete internships and training with sponsoring employers who have agreements with schools and academic institutions. F-1 students can apply for CPT after completing one full year of undergraduate or graduate studies and they can apply while they are still completing their studies.
OPT stands for Optional Practical Training. Designed to complement studies with full time practical training in a field directly related to the student’s major. F-1 students are eligible for pre or post completion OPT, while M-1 students can only apply after they have graduated from school. Here’s more information about this topic.