This template computes the number of the ISO year for the date of the gregorian calendar (or proleptic) in parameter. Any ISO year always includes an integer number, 52 or 53, of ISO weeks, each one starting on monday and ending on sunday. The ISO year:

  • starts in the morning at zero o'clock on the only monday between December the 29th of the previous gregorian year and January the 4th of the same gregorian year;
  • (the first friday/saturday/sunday of the ISO year is also the first friday/saturday/sunday of January in the same gregorian year);
  • always equals the gregorian (or proleptic) year between January the 4th, and December the 28th;
  • (the last monday/tuesday/wednesday/thirsday of the ISO year is also the last monday/tuesday/wednesday/thirsday of December in the same gregorian year);
  • finishes in the evening at midnight on the only sunday between December the 28th of the same gregorian year and January the 3rd of the next gregorian year.
Syntax:
{{WEEKDAY|année|mois|jour}}
  • The year must be astronomical (année=1 en 1 ap. J.-C. (Anno Domini), année=0 en 1 av. J.-C., année=-1 en 2 av. J.-C.).
  • The month is between 1 and 12 from january to december.
  • The day is normally between 1 and 31 (but offsets are possible to compute other dates).
Examples:
  • {{ISOYEAR|1999|12|28}} returns 1999
  • {{ISOYEAR|1999|12|29}} returns 1999
  • {{ISOYEAR|1999|12|30}} returns 1999
  • {{ISOYEAR|1999|12|31}} returns 1999
  • {{ISOYEAR|2000|1|1}} returns 1999
  • {{ISOYEAR|2000|1|2}} returns 1999
  • {{ISOYEAR|2000|1|3}} returns 2000
  • {{ISOYEAR|2000|1|4}} returns 2000
  • {{ISOYEAR|2000|12|28}} returns 2000
  • {{ISOYEAR|2000|12|29}} returns 2000
  • {{ISOYEAR|2000|12|30}} returns 2000
  • {{ISOYEAR|2000|12|31}} returns 2000
  • {{ISOYEAR|2001|1|1}} returns 2001
  • {{ISOYEAR|2001|1|2}} returns 2001
  • {{ISOYEAR|2001|1|3}} returns 2001
  • {{ISOYEAR|2001|1|4}} returns 2001
  • {{ISOYEAR|2001|12|28}} returns 2001
  • {{ISOYEAR|2001|12|29}} returns 2001
  • {{ISOYEAR|2001|12|30}} returns 2001
  • {{ISOYEAR|2001|12|31}} returns 2002
  • {{ISOYEAR|2002|1|1}} returns 2002
  • {{ISOYEAR|2002|1|2}} returns 2002
  • {{ISOYEAR|2002|1|3}} returns 2002
  • {{ISOYEAR|2002|1|4}} returns 2002
  • {{ISOYEAR|2002|12|28}} returns 2002
  • {{ISOYEAR|2002|12|29}} returns 2002
  • {{ISOYEAR|2002|12|30}} returns 2003
  • {{ISOYEAR|2002|12|31}} returns 2003
  • {{ISOYEAR|2003|1|1}} returns 2003
  • {{ISOYEAR|2003|1|2}} returns 2003
  • {{ISOYEAR|2003|1|3}} returns 2003
  • {{ISOYEAR|2003|1|4}} returns 2003
  • {{ISOYEAR|2003|12|28}} returns 2003
  • {{ISOYEAR|2003|12|29}} returns 2004
  • {{ISOYEAR|2003|12|30}} returns 2004
  • {{ISOYEAR|2003|12|31}} returns 2004
  • {{ISOYEAR|2004|1|1}} returns 2004
  • {{ISOYEAR|2004|1|2}} returns 2004
  • {{ISOYEAR|2004|1|3}} returns 2004
  • {{ISOYEAR|2004|1|4}} returns 2004
  • {{ISOYEAR|2004|12|28}} returns 2004
  • {{ISOYEAR|2004|12|29}} returns 2004
  • {{ISOYEAR|2004|12|30}} returns 2004
  • {{ISOYEAR|2004|12|31}} returns 2004
  • {{ISOYEAR|2005|1|1}} returns 2004
  • {{ISOYEAR|2005|1|2}} returns 2004
  • {{ISOYEAR|2005|1|3}} returns 2005
  • {{ISOYEAR|2005|1|4}} returns 2005
  • {{ISOYEAR|2005|12|28}} returns 2005
  • {{ISOYEAR|2005|12|29}} returns 2005
  • {{ISOYEAR|2005|12|30}} returns 2005
  • {{ISOYEAR|2005|12|31}} returns 2005
  • {{ISOYEAR|2006|1|1}} returns 2005
  • {{ISOYEAR|2006|1|2}} returns 2006
  • {{ISOYEAR|2006|1|3}} returns 2006
  • {{ISOYEAR|2006|1|4}} returns 2006
  • {{ISOYEAR|2006|12|28}} returns 2006
  • {{ISOYEAR|2006|12|29}} returns 2006
  • {{ISOYEAR|2006|12|30}} returns 2006
  • {{ISOYEAR|2006|12|31}} returns 2006
  • {{ISOYEAR|2007|1|1}} returns 2007
  • {{ISOYEAR|2007|1|2}} returns 2007
  • {{ISOYEAR|2007|1|3}} returns 2007
  • {{ISOYEAR|2007|1|4}} returns 2007
See also:
Template:YEARCC
Template:YEARYY
Template:CENTURY
Template:ISLEAPYEAR
Template:MONTHDAYS
Template:JULIANDAY
Template:WEEKDAY
Template:CURRENTISOYEAR