Six years ago, universities like MIT and Stanford first opened up free online courses to the public. Today, more than 800 schools around the world have created thousands of free online courses.

This list of 630 such free online courses that you can start this month. For this, Dhawal Shah leveraged Class Central’s database of over 10,000 courses. He also included each course’s average rating.

He sorted these courses into the following categories based on their difficulty level:

• Beginner
• Intermediate
• Advanced

Courses that are being offered for the first time are marked as [NEW].

Many of these courses are completely self-paced. The rest will start at various times later in May. You can find complete lists of the technology-related courses starting later in 2018 on Class Central’s Computer Science, Data Science, and Programming subject pages.