| Week 1 | January 2 – January 8, 2023 |
| Week 2 | January 9 – January 15, 2023 |
| Week 3 | January 16 – January 22, 2023 |
| Week 4 | January 23 – January 29, 2023 |
| Week 5 | January 30 – February 5, 2023 |
| Week 6 | February 6 – February 12, 2023 |
| Week 7 | February 13 – February 19, 2023 |
| Week 8 | February 20 – February 26, 2023 |
| Week 9 | February 27 – March 5, 2023 |
| Week 10 | March 6 – March 12, 2023 |
| Week 11 | March 13 – March 19, 2023 |
| Week 12 | March 20 – March 26, 2023 |
| Week 13 | March 27 – April 2, 2023 |
| Week 14 | April 3 – April 9, 2023 |
| Week 15 | April 10 – April 16, 2023 |
| Week 16 | April 17 – April 23, 2023 |
| Week 17 | April 24 – April 30, 2023 |
| Week 18 | May 1 – May 7, 2023 |
| Week 19 | May 8 – May 14, 2023 |
| Week 20 | May 15 – May 21, 2023 |
| Week 21 | May 22 – May 28, 2023 |
| Week 22 | May 29 – June 4, 2023 |
| Week 23 | June 5 – June 11, 2023 |
| Week 24 | June 12 – June 18, 2023 |
| Week 25 | June 19 – June 25, 2023 |
| Week 26 | June 26 – July 2, 2023 |
| Week 27 | July 3 – July 9, 2023 |
| Week 28 | July 10 – July 16, 2023 |
| Week 29 | July 17 – July 23, 2023 |
| Week 30 | July 24 – July 30, 2023 |
| Week 31 | July 31 – August 6, 2023 |
| Week 32 | August 7 – August 13, 2023 |
| Week 33 | August 14 – August 20, 2023 |
| Week 34 | August 21 – August 27, 2023 |
| Week 35 | August 28 – September 3, 2023 |
| Week 36 | September 4 – September 10, 2023 |
| Week 37 | September 11 – September 17, 2023 |
| Week 38 | September 18 – September 24, 2023 |
| Week 39 | September 25 – October 1, 2023 |
| Week 40 | October 2 – October 8, 2023 |
| Week 41 | October 9 – October 15, 2023 |
| Week 42 | October 16 – October 22, 2023 |
| Week 43 | October 23 – October 29, 2023 |
| Week 44 | October 30 – November 5, 2023 |
| Week 45 | November 6 – November 12, 2023 |
| Week 46 | November 13 – November 19, 2023 |
| Week 47 | November 20 – November 26, 2023 |
| Week 48 | November 27 – December 3, 2023 |
| Week 49 | December 4 – December 10, 2023 |
| Week 50 | December 11 – December 17, 2023 |
| Week 51 | December 18 – December 24, 2023 |
| Week 52 | December 25 – December 31, 2023 |
2023 has 52 ISO weeks. Most years have 52; a year has 53 when it starts on a Thursday (or on a Wednesday in a leap year).
Week 1 of 2023 starts on Monday, January 2, 2023 — ISO week 1 is the week containing the year's first Thursday, so it can start in late December.
=ISOWEEKNUM(A1) returns the ISO week number of the date in A1 (the numbering used on this page); =WEEKNUM(A1) uses the US Sunday-start convention. Both work in Excel and Google Sheets.