31 (calendar year or civil year). The meaning of year is the period of about 3651/4 solar days required for one revolution of the earth around the sun.
The modern world standard calendar (the gregorian calendar) presents its calendar year to be either a common year of 365 days or a leap year of 366 days, as do the julian calendars and the solar hijri.. Check the current year to align tax filings, school calendars, fiscal budgets, and software releases.