Week number 2026
Find the ISO week number and its Monday-to-Sunday date range.
29 December 2025 — 4 January 2026
| Week | Monday | Sunday |
|---|---|---|
| 2026-W01 | 29 December 2025 | 4 January 2026 |
| 2026-W02 | 5 January 2026 | 11 January 2026 |
| 2026-W03 | 12 January 2026 | 18 January 2026 |
| 2026-W04 | 19 January 2026 | 25 January 2026 |
| 2026-W05 | 26 January 2026 | 1 February 2026 |
| 2026-W06 | 2 February 2026 | 8 February 2026 |
| 2026-W07 | 9 February 2026 | 15 February 2026 |
| 2026-W08 | 16 February 2026 | 22 February 2026 |
| 2026-W09 | 23 February 2026 | 1 March 2026 |
| 2026-W10 | 2 March 2026 | 8 March 2026 |
| 2026-W11 | 9 March 2026 | 15 March 2026 |
| 2026-W12 | 16 March 2026 | 22 March 2026 |
| 2026-W13 | 23 March 2026 | 29 March 2026 |
| 2026-W14 | 30 March 2026 | 5 April 2026 |
| 2026-W15 | 6 April 2026 | 12 April 2026 |
| 2026-W16 | 13 April 2026 | 19 April 2026 |
| 2026-W17 | 20 April 2026 | 26 April 2026 |
| 2026-W18 | 27 April 2026 | 3 May 2026 |
| 2026-W19 | 4 May 2026 | 10 May 2026 |
| 2026-W20 | 11 May 2026 | 17 May 2026 |
| 2026-W21 | 18 May 2026 | 24 May 2026 |
| 2026-W22 | 25 May 2026 | 31 May 2026 |
| 2026-W23 | 1 June 2026 | 7 June 2026 |
| 2026-W24 | 8 June 2026 | 14 June 2026 |
| 2026-W25 | 15 June 2026 | 21 June 2026 |
| 2026-W26 | 22 June 2026 | 28 June 2026 |
| 2026-W27 | 29 June 2026 | 5 July 2026 |
| 2026-W28 | 6 July 2026 | 12 July 2026 |
| 2026-W29 | 13 July 2026 | 19 July 2026 |
| 2026-W30 | 20 July 2026 | 26 July 2026 |
| 2026-W31 | 27 July 2026 | 2 August 2026 |
| 2026-W32 | 3 August 2026 | 9 August 2026 |
| 2026-W33 | 10 August 2026 | 16 August 2026 |
| 2026-W34 | 17 August 2026 | 23 August 2026 |
| 2026-W35 | 24 August 2026 | 30 August 2026 |
| 2026-W36 | 31 August 2026 | 6 September 2026 |
| 2026-W37 | 7 September 2026 | 13 September 2026 |
| 2026-W38 | 14 September 2026 | 20 September 2026 |
| 2026-W39 | 21 September 2026 | 27 September 2026 |
| 2026-W40 | 28 September 2026 | 4 October 2026 |
| 2026-W41 | 5 October 2026 | 11 October 2026 |
| 2026-W42 | 12 October 2026 | 18 October 2026 |
| 2026-W43 | 19 October 2026 | 25 October 2026 |
| 2026-W44 | 26 October 2026 | 1 November 2026 |
| 2026-W45 | 2 November 2026 | 8 November 2026 |
| 2026-W46 | 9 November 2026 | 15 November 2026 |
| 2026-W47 | 16 November 2026 | 22 November 2026 |
| 2026-W48 | 23 November 2026 | 29 November 2026 |
| 2026-W49 | 30 November 2026 | 6 December 2026 |
| 2026-W50 | 7 December 2026 | 13 December 2026 |
| 2026-W51 | 14 December 2026 | 20 December 2026 |
| 2026-W52 | 21 December 2026 | 27 December 2026 |
| 2026-W53 | 28 December 2026 | 3 January 2027 |
How to read this result
ISO 8601 weeks begin on Monday. Week 1 contains 4 January, or equivalently the first Thursday of the year. An ISO week year has either 52 or 53 weeks.
Late December can belong to week 1 of the following ISO year. Early January can still belong to the final week of the preceding ISO year. The calculator displays the ISO year separately from the calendar year to make this distinction visible.
Useful answers
Do these weeks start on Sunday?
No. This tool uses ISO weeks starting on Monday. Other numbering conventions may return different values.
Which years have 53 weeks?
Some ISO years do; 2026 is one example. Each week’s date range is calculated even when it crosses a calendar-year boundary.
Data checked on 8 September 2026 · Sources and methods