Currently the Bangla year is 1409 and on 14th April, 2003. It will be 1410 in Bangladesh while in West Bengal it will be on the 15th April. The difference may be due to certain calendar changes during Gen. Ershad's military and pseudo-civilian rule in Bangladesh (1981-1990).

The zero year of the Bangla calendar coincides with the zero of the Islamic Hijri calendar since it was introduced by a Muslim Mongol conqueror of India, Emperor Akbar, descendant of Babar, Tamerlane and Chenghis Khan. Today the two calendars have diverged and have two different years.

The Bangla calendar was made a solar calendar to better coincide with harvest times and facilitate better collection of taxes. This caused the difference between the Hijri year and the Bangla year. The Hijri lunar calendar is 11/12 days shorter than the solar year and so has raced ahead. The Hijri year today (January, 2003) is 1422 while the Bangla year is 1409.

The Bengali Calendar in use today was created by Emperor Akbar (or rather someone under him) on March 10 or 11th 1584/5 AD. It amalgamated the old Indian calendar and the Islamic Hijri (Arabic) calendar and was originally called Tarikh-e-Elahi... now Bangla Shaal (possibly the name of the old calendar). That was not, however, year zero. Since Akbar had ascended the throne in the year 1556 AD and his new calendar was backdated to that year which was the year 963 in the lunar Hijri era (Islamic calendar). So the new Bangla calendar began at 963 with zero coinciding with the zero of the Hijri calendar.

Akbar's calendar used the months, Karwadin, Ardi, Vihisu, Khordad, Teer, Amardad, Shahriar, Aban, Azur, Dai, Baham and Iskander Miz. However, the months, Boishakh, Joishtho, Asharh, Srabon, Bhadra, Ashwin, Kartik, Agrahayon, Poush, Magh, Falgun, Chaitra are used. Boishakh, Joishtho, etc. are Bengali names as opposed to non-Indian names used by Akbar. The Bangla names from the older calendar prevailed.

Originally in the region, the first of Chaitra was the beginning of the new year but a new date was selected by Akbar and his administration. It was a date selected from both the Arabic and the Bengali calendars. In 963 AH (Hijri) the first arabic month, Muhurram, had coincided with Baishakh (Boishakh). So the first of Boishakh (Pahela Boishakh) was selected as the first day of the year replacing Chaitra first. Even though the names of the original months lived on, the date for the new year was changed.

The number of days in the Bengali months comes from an ancient solar treatise, the Surya Siddhanta which uses the zodiac. The days in months depends on the Sun's stay in a particular zodiac and so the number ranges from 29 to 32. The sun enters the Mesh Rashi (Aires) on 15th April and this is the first day of the Bengali month Baishakh (Boishakh) and also the first day of the year according to the new calendar. In the recent past the number of days were fixed to 30 and 31... and so dates changed.

The same calendar is used in Eastern India (Both Bengals, Assam etc.) In Assam the calendar is called the Vaskar Calendar