Any conversion of a date of the Gregorian calendar into the sexagesimal calendar is only a rough estimate. This is due to the fact that the tropical year is not made up of an integer of days but of 365.2422 days (for the same reason a birthday is never accurate, those born on February 29th know it well).

Please choose a date then push the "conversion" button to obtain its equivalent in the sexagesimal calendar (as postulated, both February 29th and March 1st return the same date, Éclose 10th).