Week Numbers

Week Numbers for the Year 2013

Knowing the week numbers for 2013 can be helpful for planning events, managing projects, or simply staying organized. Here’s a complete breakdown of all the weeks in 2013, including their start and end dates.

What Are Week Numbers?

Week numbers are a standardized way of counting the weeks in a year. Each week is assigned a number from 1 to 52 (sometimes 53), depending on how the calendar aligns with the start of the year. According to the ISO 8601 standard, each week starts on a Monday, and Week 1 is the week that contains the first Thursday of the year.

Week Number Table for 2013

Week NumberStart DateEnd Date
Week 1Dec 31, 2012Jan 6, 2013
Week 2Jan 7, 2013Jan 13, 2013
Week 3Jan 14, 2013Jan 20, 2013
Week 4Jan 21, 2013Jan 27, 2013
Week 5Jan 28, 2013Feb 3, 2013
Week 6Feb 4, 2013Feb 10, 2013
Week 7Feb 11, 2013Feb 17, 2013
Week 8Feb 18, 2013Feb 24, 2013
Week 9Feb 25, 2013Mar 3, 2013
Week 10Mar 4, 2013Mar 10, 2013
Week 11Mar 11, 2013Mar 17, 2013
Week 12Mar 18, 2013Mar 24, 2013
Week 13Mar 25, 2013Mar 31, 2013
Week 14Apr 1, 2013Apr 7, 2013
Week 15Apr 8, 2013Apr 14, 2013
Week 16Apr 15, 2013Apr 21, 2013
Week 17Apr 22, 2013Apr 28, 2013
Week 18Apr 29, 2013May 5, 2013
Week 19May 6, 2013May 12, 2013
Week 20May 13, 2013May 19, 2013
Week 21May 20, 2013May 26, 2013
Week 22May 27, 2013Jun 2, 2013
Week 23Jun 3, 2013Jun 9, 2013
Week 24Jun 10, 2013Jun 16, 2013
Week 25Jun 17, 2013Jun 23, 2013
Week 26Jun 24, 2013Jun 30, 2013
Week 27Jul 1, 2013Jul 7, 2013
Week 28Jul 8, 2013Jul 14, 2013
Week 29Jul 15, 2013Jul 21, 2013
Week 30Jul 22, 2013Jul 28, 2013
Week 31Jul 29, 2013Aug 4, 2013
Week 32Aug 5, 2013Aug 11, 2013
Week 33Aug 12, 2013Aug 18, 2013
Week 34Aug 19, 2013Aug 25, 2013
Week 35Aug 26, 2013Sep 1, 2013
Week 36Sep 2, 2013Sep 8, 2013
Week 37Sep 9, 2013Sep 15, 2013
Week 38Sep 16, 2013Sep 22, 2013
Week 39Sep 23, 2013Sep 29, 2013
Week 40Sep 30, 2013Oct 6, 2013
Week 41Oct 7, 2013Oct 13, 2013
Week 42Oct 14, 2013Oct 20, 2013
Week 43Oct 21, 2013Oct 27, 2013
Week 44Oct 28, 2013Nov 3, 2013
Week 45Nov 4, 2013Nov 10, 2013
Week 46Nov 11, 2013Nov 17, 2013
Week 47Nov 18, 2013Nov 24, 2013
Week 48Nov 25, 2013Dec 1, 2013
Week 49Dec 2, 2013Dec 8, 2013
Week 50Dec 9, 2013Dec 15, 2013
Week 51Dec 16, 2013Dec 22, 2013
Week 52Dec 23, 2013Dec 29, 2013
Week 53Dec 30, 2013Jan 5, 2014

Yes, 2013 has 53 weeks! This happens when the year starts on a Thursday or is a leap year that ends on a Thursday—allowing for that extra ISO week.

Why Are Week Numbers Useful?

Week numbers are used in a variety of scenarios across professional and personal settings:

Fun Fact

The ISO 8601 week-numbering system was first introduced in 1988 and is used by many countries around the world, especially in Europe. The U.S. doesn't commonly use it, but many global systems rely on it for consistency.

Find the Week Number of Any Date

Want to know the week number of a specific date? In PHP, you can use the DateTime object like this:

Week number is: 14

List the week numbers of the coming years.