There are many similarities in Hinduism and Buddhism. Actually, Buddhism arose from Hinduism. Some of the common beliefs in both are Karma, Reincarnation and that only path to enlightenment salvation is to live an honorable and devotional life. However, the two religions have a few key differences.
The caste system followed in Hinduism is rejected in Buddhism. Also the Gods, priesthood and rituals, which are important in Hinduism is not followed in Buddhism. Understanding from within the soul or self called ‘Atman’ or understanding Brahma, is the belief in Hinduism. In the case of Buddhism, it is not about finding the self or soul, but about finding the ‘Anatman’.
If highest life is to be attained in Hinduism, then bodily distractions have to be eliminated by the person and ultimately understand the Brahma nature within. In the case of Buddhism, the very illusion of existence is dispelled. The person adopts living a fully disciplined life, understands and moves through life as if nothing in oneself is ‘Me’. The person realizes Nirvana by doing so.
Diverse traditions are followed in Hinduism with the main reasons being its long history and its long development over a period of 3000 years. Also there was no one single founder of Hinduism. There is only a single founder of Buddhism, Siddhartha Gautama during the 6th or 5th century B.C.E.
In the development of Buddhism one of the main factors was the social caste system. It was during the time Hinduism (Brahminism) that Buddhism developed in reaction to the Hinduism which had already established itself.
Hinduism is difficult to define due to lack of text. In contrast, the texts and teachings of the exemplary and great teacher, Gautama Buddha, outline Hinduism.