Facts & conventions · regional boundary
“Bengali date” is not one calculation
Bangladesh fixed a national civil calendar through reform. West Bengal’s Panjikas continue solar-calendar calculations whose month ingress and day boundary belong to a different contract.
What this release implements
From 14 April 2019, the Bangladesh rule keeps Pohela Boishakh on 14 April, gives the first six months 31 days, Kartik through Magh and Choitro 30, and Falgun 29 days or 30 before a Gregorian leap day.
The converter refuses dates before that reform instead of projecting today’s rule backward. A future West Bengal mode must name its astronomical authority, longitude/day-boundary rule and fixtures before launch.
Why the distinction matters
Two results can both be called Bengali while disagreeing by a day or beginning a month differently. Showing the convention is part of the answer, not an implementation note. Try the named Bangladesh converter →