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Week numbers 2021

Week numbers 2021

2021 has 52 ISO weeks. Each row gives the Monday and the Sunday of the week. Print this page for a plain list of the weeks.

Weeks in 2021
52 weeks
A regular year: it has 52 ISO weeks.
Week 1 starts
Monday, 4 January 2021
the week that contains 4 January
Last week ends
Sunday, 2 January 2022
week 52
1 January 2021
Week 53 of 2020
Weeks 1 and 52 can include days of the neighbouring years: a week belongs to the year that contains its Thursday.

Printable 2021 calendars by countryWith public holidays and week numbers, as a PDF or PNG.

All weeks

The 52 weeks of 2021

  1. Week 1Mon 4 Jan – Sun, 10 Jan 2021
  2. Week 2Mon 11 Jan – Sun, 17 Jan 2021
  3. Week 3Mon 18 Jan – Sun, 24 Jan 2021
  4. Week 4Mon 25 Jan – Sun, 31 Jan 2021
  5. Week 5Mon 1 Feb – Sun, 7 Feb 2021
  6. Week 6Mon 8 Feb – Sun, 14 Feb 2021
  7. Week 7Mon 15 Feb – Sun, 21 Feb 2021
  8. Week 8Mon 22 Feb – Sun, 28 Feb 2021
  9. Week 9Mon 1 Mar – Sun, 7 Mar 2021
  10. Week 10Mon 8 Mar – Sun, 14 Mar 2021
  11. Week 11Mon 15 Mar – Sun, 21 Mar 2021
  12. Week 12Mon 22 Mar – Sun, 28 Mar 2021
  13. Week 13Mon 29 Mar – Sun, 4 Apr 2021
  14. Week 14Mon 5 Apr – Sun, 11 Apr 2021
  15. Week 15Mon 12 Apr – Sun, 18 Apr 2021
  16. Week 16Mon 19 Apr – Sun, 25 Apr 2021
  17. Week 17Mon 26 Apr – Sun, 2 May 2021
  18. Week 18Mon 3 May – Sun, 9 May 2021
  19. Week 19Mon 10 May – Sun, 16 May 2021
  20. Week 20Mon 17 May – Sun, 23 May 2021
  21. Week 21Mon 24 May – Sun, 30 May 2021
  22. Week 22Mon 31 May – Sun, 6 Jun 2021
  23. Week 23Mon 7 Jun – Sun, 13 Jun 2021
  24. Week 24Mon 14 Jun – Sun, 20 Jun 2021
  25. Week 25Mon 21 Jun – Sun, 27 Jun 2021
  26. Week 26Mon 28 Jun – Sun, 4 Jul 2021
  27. Week 27Mon 5 Jul – Sun, 11 Jul 2021
  28. Week 28Mon 12 Jul – Sun, 18 Jul 2021
  29. Week 29Mon 19 Jul – Sun, 25 Jul 2021
  30. Week 30Mon 26 Jul – Sun, 1 Aug 2021
  31. Week 31Mon 2 Aug – Sun, 8 Aug 2021
  32. Week 32Mon 9 Aug – Sun, 15 Aug 2021
  33. Week 33Mon 16 Aug – Sun, 22 Aug 2021
  34. Week 34Mon 23 Aug – Sun, 29 Aug 2021
  35. Week 35Mon 30 Aug – Sun, 5 Sept 2021
  36. Week 36Mon 6 Sept – Sun, 12 Sept 2021
  37. Week 37Mon 13 Sept – Sun, 19 Sept 2021
  38. Week 38Mon 20 Sept – Sun, 26 Sept 2021
  39. Week 39Mon 27 Sept – Sun, 3 Oct 2021
  40. Week 40Mon 4 Oct – Sun, 10 Oct 2021
  41. Week 41Mon 11 Oct – Sun, 17 Oct 2021
  42. Week 42Mon 18 Oct – Sun, 24 Oct 2021
  43. Week 43Mon 25 Oct – Sun, 31 Oct 2021
  44. Week 44Mon 1 Nov – Sun, 7 Nov 2021
  45. Week 45Mon 8 Nov – Sun, 14 Nov 2021
  46. Week 46Mon 15 Nov – Sun, 21 Nov 2021
  47. Week 47Mon 22 Nov – Sun, 28 Nov 2021
  48. Week 48Mon 29 Nov – Sun, 5 Dec 2021
  49. Week 49Mon 6 Dec – Sun, 12 Dec 2021
  50. Week 50Mon 13 Dec – Sun, 19 Dec 2021
  51. Week 51Mon 20 Dec – Sun, 26 Dec 2021
  52. Week 52Mon, 27 Dec 2021 – Sun, 2 Jan 2022

What week is it now?202020222026

How it works

Week number

2021 has 52 ISO weeks. It begins on a Friday; only years that begin on a Thursday, or on a Wednesday in a leap year, have 53 weeks.

ISO 8601 numbers the weeks of a year from 1 to 52 or 53. Weeks run from Monday to Sunday, and week 1 is the week that holds the first Thursday of the year, which is also the week that contains 4 January. Each week belongs to the year that contains its Thursday.

Questions

Good to know

How many weeks are there in 2021?

2021 has 52 ISO weeks (52 or 53 in any year).

When does week 1 of 2021 start?

Week 1 of 2021 runs Mon 4 Jan – Sun, 10 Jan 2021. It is the week that contains 4 January 2021.

Which years after 2021 have 53 weeks?

2026, 2032, 2037, 2043. A year has 53 ISO weeks when 1 January is a Thursday, or a Wednesday in a leap year.

How do I get a printable list or calendar?

Use the print button above for this list of weeks, or open the printable calendar of your country: it marks the public holidays and shows the ISO week number of every week.