Which Bangla calendar this uses
Bangladesh revised the official Bangla calendar so that Pohela Boishakh is always 14 April. The first five months (বৈশাখ to ভাদ্র) have 31 days. The next six have 30. চৈত্র has 30 days, or 31 in a Gregorian leap year. That is the system this converter follows.
West Bengal and some almanacs still use older month lengths and a different New Year rule. If you are matching a Kolkata panjika, the date can differ by a day. For Bangladesh government letters, school calendars and newspaper datelines, the 14 April rule is the one people expect.
Bangla year ≈ Gregorian year − 593 after 14 April, and − 594 before that. 20 August 2026 is in ১৪৩৩ বঙ্গাব্দ. Always write the weekday if the document is a legal notice; the converter shows it for Gregorian input.
Pair this with the number converter if you need the day and year in Bangla digits for a letterhead.