

With this method, the first week starts on the 1st of January, and each subsequent week is numbered sequentially (i.e. Find more info on our main week number page. Under Display options, select or clear the Show week numbers in the month view and in the Date Navigator check box.
#WEEK NUMBER FOR 2016 ISO#
Please note that there are multiple systems for week numbering, this is the ISO week date standard (ISO-8601), other systems use weeks starting on Sunday (US) or Saturday (Islamic). Similar to the US method, the first week starts on the 1st of January, but subsequent weeks begin on Mondays. All weeks are starting on Monday and ending on Sunday. This starts at 1 for the week containing the first Thursday.

Enter a start date and an end date and the week calculator will return the number of weeks and days separating the two. The format mask IW returns the ISO week number of the year. In this method, the first week of the year begins on the 1st of January, and subsequent weeks start on Sundays. Below is a week between dates calculator. Specifically, 1st, 2nd, and 3rd of January can be included in the last week of the previous year, or 29th, 30th, and 31st of December can be included in the first week of next year. Some days from the previous or next year may be included in the first or last week. The first week of a year is the week that includes the first Thursday of the year or the 4th of January.

The week number is computed as defined in ISO 8601, the official standard in Europe. All weeks are starting on Monday and ending on Sunday (ISO-8601). The Week Number Calculator provides different methods of calculating week numbers.
