Because the system and cycle of Gregorian calendar and trunk and branch calendar are completely different, the conversion between them is more complicated. Especially, it is very difficult to solve the daily budget of a public office. At present, it is mainly solved by querying the perpetual calendar. After painstaking research, the author explored and derived a calendar formula for calculating the daily branch and the public branch, which is called "high daily branch formula" for short.
The formula is simple, accurate, scientific and practical by inserting century constants and month cardinality, which completely solves the long-standing problem of calendar conversion. It is of great practical significance on the specific issue of "if you don't look up the calendar, the sun column will know early"