It is a solar-based calendar. It begins in the year that Báb (Martyr-Herald of the Bahá’í faith) declared that he was the forerunner of a new Manifestation of God that would soon appear. This was in 1260 of the Muslim calendar or 1844 of the Christian calendar.
The day begins and ends at sunset. The nineteen days of a month are named for attributes of God. The nineteen months have the same names as the days. The year is divided into fifty-two weeks. The seven days of the week are also named after attributes of God. The first day of each month is a fast day.
To balance this year of 361 days with the solar year, four days are added in common years and five days in leap years. Leap years occur once in four years unless a further adjustment to have the first day of the year occur with the vernal equinox is necessary.