Hare Krishna and Hinduism are usually regarded to be the same as they are mostly considered to be the same religion. However, there are a lot of differences between the two. Hinduism is the largest religion in India, and its beliefs are based on the existence of a supreme oneness personified in many natures or forms.
As a result of this, its beliefs and practices are a fusion of a lot of traditions, and that is why Hindus have a lot of demigods that they worship. On the other hand, Hare Krishna has most of its beliefs based on the fact that there is only one God. Those who practice Hare Krishna have been taught to continuously worship in the consciousness that there is only one God, which is God Krishna.
They believe God Krishna is one no matter what other religions choose to call it. While Hinduism is usually regarded as a religion, followers of Hare Krishna believe that Hare Krishna is not a religion but a consciousness.