How the Bangla Calendar Works: Months, Leap Years and the 2019 Revision

How Bangabda works: four rules

The Bangla calendar used officially in Bangladesh (Bangabda, বঙ্গাব্দ) was last revised by Bangla Academy in 2019. Its rules are the same every year and easy to remember:

1. The year starts on 14 April, which is 1 Boishakh, or Pohela Boishakh. 13 April is the last day of Chaitra.
2. The first six months, Boishakh to Ashwin, have 31 days each.
3. Kartik, Agrahayan, Poush, Magh and Chaitra have 30 days.
4. Falgun has 29 days, or 30 in a leap year.

To find the Bangla year, subtract 593 from the English year on or after 14 April, or 594 before it. So 14 April 2026 starts 1433, and 1 January 2027 is still 1433 (2027 − 594). To skip the counting, use the Bangla Date Converter; it follows exactly these rules.

Bangla calendar 1433: when each month runs

Because the month lengths are fixed, each Bangla month starts on the same English date every year. Bangabda 1433 runs from 14 April 2026 to 13 April 2027:

The start dates stay the same in later years; only the last day of Falgun moves by a day in a leap year (see below).

Worked example: what is the Bangla date today?

Let’s find the Bangla date for 28 October 2026.

1. It is after 14 April, so the year is 2026 − 593 = 1433.
2. The table shows Kartik starts on 17 October, so 28 October is day 28 − 17 + 1 = 12 of Kartik.
3. Kartik is a month of Hemonto, late autumn.

Answer: 28 October 2026, a Wednesday, is ১২ কার্তিক ১৪৩৩ বঙ্গাব্দ (12 Kartik 1433). The next day, 29 October, is 13 Kartik. Bangla dates are conventionally written with Bangla digits, as shown.

Watch the year boundary: 13 April 2026 was 30 Chaitra 1432, the last day of the year, and the next day, 14 April, was 1 Boishakh 1433. So for any date from 1 January to 13 April, subtract 594, not 593; that is where most hand calculations go wrong.

The other direction works the same way: which day is 31 Ashwin 1433? Ashwin starts on 16 September, so its 31st day is 16 October 2026. To see the Bangla date as soon as you open a page, go to the Bangla Date Converter; it shows today’s Bangla date, season and weekday from your device’s date.

What the 2019 revision changed

Under the old rules the first five months had 31 days and the other seven had 30. In 2015 a committee led by former Bangla Academy director general Shamsuzzaman Khan recommended a revision, and the new rules took effect in 2019: Ashwin also got 31 days, and Falgun got 29 (30 in a leap year). Ashwin had 31 days for the first time in 2019.

There were two aims: to keep in step with the English calendar, and to fix the national days to the Bangla dates they fell on in 1952 and 1971. Before, 21 February fell on 8 Falgun in some years and 9 Falgun in others. For the same reason Pohela Falgun is now always 14 February, ending the habit of marking it on 13 February.

West Bengal and other Indian states follow the traditional calendar, whose month lengths change from year to year with astronomical calculations, so the same day can have a different Bangla date in the two countries. A calendar printed before 2019 can also be a day different from today’s rules.

Why Falgun has 30 days in a leap year

Falgun runs from 14 February to the middle of March, so 29 February always falls in it. In a year with 29 February, Falgun gets an extra day. That way Chaitra still starts on 15 March and Pohela Boishakh stays on 14 April.

• Falgun 1433 (February–March 2027) has 29 days; there is no 30 Falgun 1433.
• Falgun 1434 runs from 14 February to 14 March 2028, 30 days. 29 February 2028 is 16 Falgun 1434, and 15 March 2028 is 1 Chaitra.

Press reports describe the rule as “every four years”. Our converter uses the full Gregorian rule (so 2100 is not a leap year), because only that keeps the two calendars together for good.

The six seasons and the national days’ Bangla dates

Six seasons of two months each, starting from Boishakh: Grishma (summer: Boishakh, Joishtho), Borsha (monsoon: Asharh, Srabon), Shorot (autumn: Bhadro, Ashwin), Hemonto (late autumn: Kartik, Agrahayan), Sheet (winter: Poush, Magh) and Boshonto (spring: Falgun, Chaitra).

Since the revision, the national days fall on the same Bangla date every year:

• 21 February (Shaheed Dibosh, International Mother Language Day) = 8 Falgun
• 26 March (Independence Day) = 12 Chaitra
• 16 December (Victory Day) = 1 Poush
• 14 April (Pohela Boishakh, Bangla New Year) = 1 Boishakh
• 14 February = Pohela Falgun, the first day of spring

By the same rules, Rabindra Jayanti (25 Boishakh) is always 8 May and Nazrul Jayanti (11 Joishtho) is 25 May. Coming up: 16 December 2026 is 1 Poush 1433, 21 February 2027 is 8 Falgun 1433, and 14 April 2027 is 1 Boishakh 1434. To count the days left until Pohela Boishakh or any other date, use the Date Difference Calculator.

Sources

Month lengths, the leap-year Falgun and 21 February = 8 Falgun under the 2019 revision: Dhaka Tribune (22 October 2019, quoting Bangla Academy secretary Mohammad Anwar Hossain). The fixed national-day dates (8 Falgun, 12 Chaitra, 1 Poush) and Pohela Falgun on 14 February: The Daily Star (13 February 2020). Both checked again on 29 October 2026.