Bengali calendar

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বঙ্গাব্দ Bônggabdô
Bengali Calendar
মাস Mas
কাল/ঋতু Kal/Ritu
বৈশাখ Bôishakh
গ্রীষ্ম Grishmô
জ্যৈষ্ঠ Jyôishţhô
আষাঢ় Ashaŗh
বর্ষা Bôrsha
শ্রাবণ Shrabôn
ভাদ্র Bhadrô
শরৎ Shôrôt
আশ্বিন Ashbin
কার্তিক Kartik
হেমন্ত Hemôntô
Late Autumn
অগ্রহায়ণ Ogrôhayôn
পৌষ Poush
শীত Shīt
মাঘ Magh
ফাল্গুন Falgun
বসন্ত Bôsôntô
চৈত্র Chôitrô

The Bengali Calendar (Bengali: বঙ্গাব্দ Bônggabdô or বাংলা সন Bangla Sôn) or Bangla Calendar is the calendar native to the region of Bengal. It is recognized as the national and official calendar in Bangladesh. The New Year is Pôhela Bôishakh, which falls on 14 April or 15 April in the Western calendar. The current Bengali year is 1421. The Bengali year is 594 less than the AD or CE year in the Western calendar if it is before Pôhela Bôishakh, or 593 less if after Pôhela Bôishakh.


The origin of Bônggabdô or Bengali Year (Bangla Year) is debated, with primarily two hypotheses, but the historicity of neither can be proved to date. The development of the Bengali calendar is often attributed to King of Gour, Shashanka as the starting date falls squarely within his reign.

During the period of Mughal Emperor, Akbar the renowned grandson of Babur was the 3rd Mughal Emperor who officially re-introduced the Bengali Calendar in order to make tax collection relatively easier in Bengal, Akbar changed the practice of agricultural tax collection according to Hijri calendar and ordered an improvement of the calendar systems, because the Hijri calendar being a lunar calendar- did not agree with the harvest sessions and eventually the farmers in Bengal faced severe difficulties in paying taxes out of season.

The regal astrologer of Emperor Akbar's reign, Aamir Fatehullah Siraji was the one who in fact developed the Bengali calendar, after working out a research on the lunar Hijri and Solar calendars. The distinctive characteristic of the Bengali year was that rather than being a lunar calendar, it was based on a union of the solar and lunar year. This was essentially a great promotion as the solar and lunar years were formulated in very diverse systems.

Primarily this calendar was named as "Fasli Sôn" and then Bônggabdô or Bengali Year was launched on 10/11 March 1584, but was dated from 5 November 1556 or 963 Hijri. This was the day that Akbar defeated Himu in the clash of Panipat to ascend the throne.

Akbar ordered all dues to be resolved on the last day of চৈত্র Chôitrô. The next day was the first day of the New Year (পহেলা বৈশাখ Pôhela Bôishakh), the day for a new opening; landlords used to allocate sweets among their tenants and businessmen would commence a হালখাতা Halkhata (new financial records book) and lock their old ones. Vendors used to provoke their consumers to allocate sweets and renew their business relationship with them. There were fairs and festivities all over and gradually Pôhela Bôishakh became a day of celebration.



The Bengali calendar consists of 6 seasons, with each season comprising two months. Beginning from Pôhela Bôishakh, they are Grishmô (গ্রীষ্ম) or Summer; Bôrsha (বর্ষা) or Rainy/Monsoon season; Shôrôt (শরৎ) or Autumn; Hemôntô (হেমন্ত) or the Dry season; Šhit (শীত) or Winter; and Bôsôntô (বসন্ত) or Spring.

As the traditional Bengali calendar used in West Bengal is sidereal and does not correspond to the actual tropical movement of the earth. Hence after some centuries the months will shift far away from the actual seasons. But the new revised tropical version of the Bengali calendar used in Bangladesh will continue to maintain the seasons as mentioned above.


The names of the twelve months of the Bengali calendar are based on the names of the নক্ষত্র nôkkhôtrô (lunar mansions): locations of the moon with respect to particular stars during the lunar cycle. These names were derived from the Surya Siddhanta.

Month name (Bengali) Romanization Days (Traditional non-revised sidereal version - West Bengal) Days (New revised tropical version - Bangladesh) Month name origin - name of the stars (Bengali) Romanization
বৈশাখ Bôishakh 30 / 31 31 বিশাখা Bishakha
জ্যৈষ্ঠ Jyôishţhô 31 / 32 31 জ্যেষ্ঠা Jyeshţha
আষাঢ় Ashaŗh 31 / 32 31 উত্তরাষাঢ়া Uttôrashaŗha
শ্রাবণ Shrabôn 31 / 32 31 শ্রবণা Shrôbôna
ভাদ্র Bhadrô 31 / 32 31 পূর্বভাদ্রপদ Purbôbhadrôpôd
আশ্বিন Ashbin 31 / 30 30 অশ্বিনী Ôshbini
কার্তিক Kartik 29 / 30 30 কৃত্তিকা Krittika
অগ্রহায়ণ Ogrôhayôn 29 / 30 30 মৃগশিরা Mrigôshira
পৌষ Poush 29 / 30 30 পুষ্যা Pushya
মাঘ Magh 29 / 30 30 মঘা Môgha
ফাল্গুন Falgun 29 / 30 30 / 31 উত্তরফাল্গুনী Uttôrfalguni
চৈত্র Chôitrô 30 / 31 30 চিত্রা Chitra


The Bengali Calendar incorporates the seven-day week as used by many other calendars. The names of the days of a week in the Bengali Calendar are based on celestial objects, or নবগ্রহ nôbôgrôhô.

Day name (English) Day name (Bengali) Romanization Day name origin (Bengali) Romanization and meaning
Sunday রবিবার Rôbibar রবি Rôbi
Monday সোমবার Sombar সোম Som (Moon)
Tuesday মঙ্গলবার Mônggôlbar মঙ্গল Mônggôl (Mars)
Wednesday বুধবার Budhbar বুধ Budh (Mercury)
Thursday বৃহস্পতিবার Brihôspôtibar বৃহস্পতি Brihôspôti (Jupiter)
Friday শুক্রবার Shukrôbar শুক্র Shukrô (Venus)
Saturday শনিবার Shônibar শনি Shôni (Saturn)

In the Bengali calendar, the day begins and ends at sunrise, unlike in the Gregorian calendar, where the day starts at midnight.

Revised Bengali calendar[edit]

The Bengali calendar in Bangladesh was modified by a committee headed by Muhammad Shahidullah under the auspices of the Bangla Academy on 17 February 1966.

The length of a year in the Bengali calendar, as in the Gregorian calendar, is counted as 365 days. However, the actual time taken by the earth in its revolution around the sun is 365 days 5 hours 48 minutes and 47 seconds. To make up this discrepancy, the Gregorian calendar adds an extra day, to make a leap year, to the month of February every fourth year (except in years divisible by 100 but not by 400). The Bengali calendar, which was based on astronomical calculations, did not make this extra leap year adjustment. Bengali months, too, were of different lengths. To counter this discrepancy, and to make the Bengali calendar more precise, the following recommendations of the Bangla Academy are followed:

  • The first five months of the year from Bôishakh to Bhadrô will consist of 31 days each.
  • The remaining seven months of the year from Ashbin to Chôitrô will consist of 30 days each.
  • In every leap year of the Gregorian calendar, an additional day will be added in the month of Falgun, which is just 14 days after 29 February. (Modified without material change).

The revised calendar was officially adopted in Bangladesh in 1987. However, it is not followed in the neighboring state of West Bengal where the traditional calendar continues to be followed because of Hindu religious festivals are celebrated based on a particular lunar day and traditional calendar combination.

Revised and non-revised versions[edit]

Pôhela Bôishakh in West Bengal is celebrated on 14/15 April. However according to the revised version of the calendar in Bangladesh, Pôhela Bôishakh now always falls on 14 April in Bangladesh. The mathematical difference between the sidereal (non-revised) and the tropical (revised) calendar accounts for the difference of starting the new year in West Bengal and Bangladesh. Because of this the length of the months are also not fixed in the sidereal calendar (non-revised), but rather are based on the true movement of the sun.

Leap year[edit]

Although the sidereal (non-revised) calendar followed in West Bengal has the number of days in the months are determined by the true motion of the Sun through the zodiac. In this calendar seven is subtracted from the year, and the result is divided by 39. If after the division the remainder (= (year  - 7) / 39) is zero or is evenly divisible by 4, the year is then designated as a leap year and contains 366 days, with the last month Chôitrô, taking 31 days. There are 10 leap years in every 39 years, although an extraordinary revision may be required over a long time.[citation needed]

According to the new Revised calendar system in Bangladesh, Falgun (which begins mid-February) has 31 days every four years. To keep pace with the Gregorian calendar, the Bengali leap years are those whose corresponding Gregorian calendar year is counted as a leap year. For example, Falgun 1410 was considered a Bengali leap month, as it fell during the Gregorian leap month of February 2004.


The usage and popularity of the Bengali calendar in Bengal region is due to its adaptation to the unique seasonal patterns of the region. Bengal has a climate that is best divided into six seasons, including the monsoon or rainy season and the dry season in addition to spring, summer, fall, and winter.

In general usage, the Bengali Calendar has been replaced by the Gregorian Calendar, although it is still essential for marking holidays specific to Bengali culture (e.g. Pôhela Bôishakh, etc.), and for marking the seasons of the year. The Bengali calendar is the official calendar in Bangladesh and is recognized as National calendar by the Government of Bangladesh, whose offices date all their correspondence with the Bengali date as well as the Gregorian one. Every Bengali and English newspaper in Bangladesh and West Bengal prints the day's date according to the Bengali Calendar alongside the corresponding date of the Gregorian Calendar.

Some newspapers in Bangladesh also add a third date, following the Islamic Hijri calendar. Thus might be quite common in Bangladesh to find the date written three times, e.g. "১৫ ফাল্গুন ১৪১২, ১৭ মুহররম ১৪২৭, ২৭ ফেব্রুআরি ২০০৬" (15 Falgun 1412, 17 Muharrom 1427, 27 February 2006) under the newspaper title.

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