The Bengali Calendar or Bangla Calendar, colloquially, is a solar calendar used in the Bengal region of the South Asia. A revised version of the calendar is the national and official calendar in Bangladesh and an earlier version of the calendar is followed in the Indian states of West Bengal, Tripura and Assam. Unlike the traditional Indian Hindu calendar which starts with the month of Chaitra, the Bengali calendar starts with Boishakh because of the reforms made during the reign of the Mughal Emperor Akbar in Mughal Bengal. The first day of the Bengali year is known as Pohela Boishakh which is a public holiday in Bangladesh.

The Bengal Subah, also referred to as Mughal Bengal, was the largest subdivision of the Mughal Empire encompassing much of the Bengal region, which includes modern-day Bangladesh, the Indian state of West Bengal, and some parts of the present-day Indian states of Bihar, Jharkhand and Odisha between the 16th and 18th centuries. The state was established following the dissolution of the Bengal Sultanate, a major trading nation in the world, when the region was absorbed into the Mughal Empire. Bengal was the wealthiest region in the Indian subcontinent.