Reformed Bengali Calendar
The reformed Bengali calendar was introduced on February 17, 1966.
- be an improvement on the traditional calendar.
- based on the tropical year .
- Have fixed length months.
The year count
The years are counted continuously according to the Bengali Era (BS). This count builds on the count of the traditional Bengali calendar. The Mughal Mogul Akbar stipulated in 1584 that the count should coincide with the Hijra count . The year of his accession to the throne 963 AH was therefore the year 963 BS = 1555/56 AD. To determine the year AD for a year of the Bengali era, add 593 or 594, depending on the season.
The beginning of the year
The beginning of the year begins when the sun enters the zodiac sign Aries.
The year has a length of 365 days. However, since the tropical year currently has a length of 365.242190 days, an additional leap day has to be inserted approximately every four years in order to match the seasons. In the leap year, the month of Falgun is extended by 1 day to 31 days. The leap years are linked to the leap years of the Gregorian calendar. Add 594 to the Bengali year and apply the switching rules of the Gregorian calendar: If the number is divisible by 4 without a remainder, the year is a leap year, but if the number is also divisible by 400 without a remainder, the year is not a leap year. Which dates of the Reformed Bengali calendar shift in the leap year compared to the Gregorian calendar can be seen in the following table:
|Common year||Leap year|
With a length of 146,097 days, the calendar deviates by 0.124 days in 400 tropical years or by 1 day in around 3225 years.
The beginning of the month
The month begins roughly with the entry of the sun into a new zodiac sign.
The length of the month
Since the earth's orbit around the sun is an ellipse, the time it takes for the sun to apparently travel through the ecliptic varies for the individual zodiac signs. To adjust the length of the months to the apparent course of the sun, the first five months have 30 days, the remaining seven months 31 days.
The month names
The months were named like the months in the traditional Bengali calendar. The following table gives the Bengali names of the months, their length and the corresponding beginning of the month in the Gregorian calendar:
|Bengali||transcription||Month length in days||Beginning of the month in the
|শ্রাবণ||Shrabon||31||16th of July|
|অগ্রহায়ণ||Ogrohayon||30th||15th of November|
The days of a month are counted from 1 to 30 or 31. The Bengali numerals can be found under Bengali numerals .
The week division is of Babylonian-Greek origin. The names are derived from the corresponding deities. The names are listed in the following table:
|bengali||transcription||in the Gregorian
- FK Ginzel: Handbook of mathematical and technical chronology, Leipzig 1906, Vol. I, p. 394