Week number 2027
Find the ISO week number and its Monday-to-Sunday date range.
4 January 2027 — 10 January 2027
| Week | Monday | Sunday |
|---|---|---|
| 2027-W01 | 4 January 2027 | 10 January 2027 |
| 2027-W02 | 11 January 2027 | 17 January 2027 |
| 2027-W03 | 18 January 2027 | 24 January 2027 |
| 2027-W04 | 25 January 2027 | 31 January 2027 |
| 2027-W05 | 1 February 2027 | 7 February 2027 |
| 2027-W06 | 8 February 2027 | 14 February 2027 |
| 2027-W07 | 15 February 2027 | 21 February 2027 |
| 2027-W08 | 22 February 2027 | 28 February 2027 |
| 2027-W09 | 1 March 2027 | 7 March 2027 |
| 2027-W10 | 8 March 2027 | 14 March 2027 |
| 2027-W11 | 15 March 2027 | 21 March 2027 |
| 2027-W12 | 22 March 2027 | 28 March 2027 |
| 2027-W13 | 29 March 2027 | 4 April 2027 |
| 2027-W14 | 5 April 2027 | 11 April 2027 |
| 2027-W15 | 12 April 2027 | 18 April 2027 |
| 2027-W16 | 19 April 2027 | 25 April 2027 |
| 2027-W17 | 26 April 2027 | 2 May 2027 |
| 2027-W18 | 3 May 2027 | 9 May 2027 |
| 2027-W19 | 10 May 2027 | 16 May 2027 |
| 2027-W20 | 17 May 2027 | 23 May 2027 |
| 2027-W21 | 24 May 2027 | 30 May 2027 |
| 2027-W22 | 31 May 2027 | 6 June 2027 |
| 2027-W23 | 7 June 2027 | 13 June 2027 |
| 2027-W24 | 14 June 2027 | 20 June 2027 |
| 2027-W25 | 21 June 2027 | 27 June 2027 |
| 2027-W26 | 28 June 2027 | 4 July 2027 |
| 2027-W27 | 5 July 2027 | 11 July 2027 |
| 2027-W28 | 12 July 2027 | 18 July 2027 |
| 2027-W29 | 19 July 2027 | 25 July 2027 |
| 2027-W30 | 26 July 2027 | 1 August 2027 |
| 2027-W31 | 2 August 2027 | 8 August 2027 |
| 2027-W32 | 9 August 2027 | 15 August 2027 |
| 2027-W33 | 16 August 2027 | 22 August 2027 |
| 2027-W34 | 23 August 2027 | 29 August 2027 |
| 2027-W35 | 30 August 2027 | 5 September 2027 |
| 2027-W36 | 6 September 2027 | 12 September 2027 |
| 2027-W37 | 13 September 2027 | 19 September 2027 |
| 2027-W38 | 20 September 2027 | 26 September 2027 |
| 2027-W39 | 27 September 2027 | 3 October 2027 |
| 2027-W40 | 4 October 2027 | 10 October 2027 |
| 2027-W41 | 11 October 2027 | 17 October 2027 |
| 2027-W42 | 18 October 2027 | 24 October 2027 |
| 2027-W43 | 25 October 2027 | 31 October 2027 |
| 2027-W44 | 1 November 2027 | 7 November 2027 |
| 2027-W45 | 8 November 2027 | 14 November 2027 |
| 2027-W46 | 15 November 2027 | 21 November 2027 |
| 2027-W47 | 22 November 2027 | 28 November 2027 |
| 2027-W48 | 29 November 2027 | 5 December 2027 |
| 2027-W49 | 6 December 2027 | 12 December 2027 |
| 2027-W50 | 13 December 2027 | 19 December 2027 |
| 2027-W51 | 20 December 2027 | 26 December 2027 |
| 2027-W52 | 27 December 2027 | 2 January 2028 |
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