Hey aspirant, Hope you are doing well!

No both of these are considered to be very different from each other. Post graduation diploma is not equivalent to a Master's degree. PG diploma is of a shorter duration than of a full time masters. It usually costs much lesser too. PG diploma is just an introduction into a new field of discipline which in turn helps to get jobs and acts as an additional qualification for people. Whereas, masters is the advanced stage of studying a field. It offers specialisation. For masters , the minimum eligibility is a bachelor's degree. On the other hand, for PG diploma the minimum qualification is not so rigid. After high school or a bachelor's degree anybody can go for a PG diploma in a particular field. Moreover, master's degree offers a wide variety of career options.

Hope it helps! All the very best for you future endeavours.