Reformed Bengali Calendar

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The reformed Bengali calendar was introduced on February 17, 1966.


The traditional Bengali calendar is based on the sidereal year , and the months vary in length in different years. The new calendar should:

  • be an improvement on the traditional calendar.
  • based on the tropical year .
  • Have fixed length months.

The year

The year is a tropical year and begins when the sun enters the Aries zodiac sign. The common year consists of 365 days, the leap year of 366 days. The leap day is added to the month before last.

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 circuit

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
bengali Gregorian bengali Gregorian
ফাল্গুন 1. Falgun 13. February ফাল্গুন 1. Falgun 13. February
: : : :
১৬ ফাল্গুন 16. Falgun 28. February ১৬ ফাল্গুন 16. Falgun 28. February
১৭ ফাল্গুন 17th Falgun 1. March ১৭ ফাল্গুন 17th Falgun 29 February
১৮ ফাল্গুন 18th Falgun 2. March ১৮ ফাল্গুন 18th Falgun 1. March
: : : :
৩০ ফাল্গুন 30th Falgun 14th March ৩০ ফাল্গুন 30th Falgun 13. March
≡≡≡≡ ≡≡≡≡ ৩১ ফাল্গুন 31. Falgun 14th March
চৈত্র 1. Choitro 15th March চৈত্র 1. Choitro 15th March
: : : :
৩০ চৈত্র 30th Choitro 13. April ৩০ চৈত্র 30th Choitro 13. April

The precision

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 month

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
Gregorian calendar
বৈশাখ Boishakh 31 April 14th
জ্যৈষ্ঠ Jyoishtho 31 May 15
আষাঢ় Asharh 31 15th June
শ্রাবণ Shrabon 31 16th of July
ভাদ্র Bhadro 31 August 16
আশ্বিন Ashbin 30th 16th September
কার্তিক Kartik 30th October, 16th
অগ্রহায়ণ Ogrohayon 30th 15th of November
পৌষ Poush 30th 15th December
মাঘ Magh 30th January 14th
ফাল্গুন Falgun 30th 13th February
চৈত্র Choitro 30th March, 15

The days of a month are counted from 1 to 30 or 31. The Bengali numerals can be found under Bengali numerals .

The week

The week

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
সোমবার Shombar Monday
মঙ্গলবার Monggolbar Tuesday
বুধবার Budhbar Wednesday
বৃহস্পতিবার Brihoshpotibar Thursday
শুক্রবার Shukrobar Friday
শনিবার Shonibar Saturday
রবিবার Robibar Sunday

See also

Web links


  1. Astronomical Definitions Year

Individual evidence

  1. FK Ginzel: Handbook of mathematical and technical chronology, Leipzig 1906, Vol. I, p. 394