Hindu calendar is like a planner that helps Hindus keep track of important days, like birthdays and festivals. It is based on the movement of the moon and stars, so it is not the same as the calendar we use in everyday life. It has twelve months, called lunar months, and each month has two fortnights, or two halves. The Hindu calendar also keeps track of the stars and the position of the sun, so Hindus can plan important events like weddings and religious ceremonies.