ISO, week 1
- Input
- 2027-W01
- Expected output
- 2027-01-04 a 2027-01-10
Monday to Sunday.
Carregando ferramenta… / Loading tool…
2027 week numbers calendar
The tool's table lists the 52 ISO weeks of 2027 with start and end dates, and you can switch to the US system, change the year and copy everything into a spreadsheet. This page sums up the 2027 points that confuse most.
Monday to Sunday.
Ends in 2028.
Sunday to Saturday, with January 1.
The last full week of the year.
Thursday, start of the third quarter.
The big number at the top shows today's week, calculated from your device's date. On Monday, November 2, 2026, it is week 45 in both ISO 8601 and the US system; on the Sunday before, November 1, the systems differ (44 in ISO, 45 in the US).
52 weeks, numbered 1 to 52. 2026 had 53, which is why January 1, 2027 is still week 53 of 2026.
Yes. The Copy table button carries the Week, Start and End columns separated by tabs, which spreadsheets paste straight into columns.
Type the year in the table field, from 1583 to 9998. The table and the chosen system (ISO or US) are kept in the copied link.
Christmas, December 25, a Saturday, is week 2027-W51 in ISO and 2027-W52 in the US. New Year's Eve, December 31, is 2027-W52 in ISO and already 2028-W01 in the US, while January 1, 2028 is still 2027-W52 in ISO.
Reading today's date...
52 weeks, from the first (starts 01/04/2027) to the last (ends 01/02/2028).
| Week | Start | End |
|---|---|---|
| 1 | Mon 01/04/2027 | Sun 01/10/2027 |
| 2 | Mon 01/11/2027 | Sun 01/17/2027 |
| 3 | Mon 01/18/2027 | Sun 01/24/2027 |
| 4 | Mon 01/25/2027 | Sun 01/31/2027 |
| 5 | Mon 02/01/2027 | Sun 02/07/2027 |
| 6 | Mon 02/08/2027 | Sun 02/14/2027 |
| 7 | Mon 02/15/2027 | Sun 02/21/2027 |
| 8 | Mon 02/22/2027 | Sun 02/28/2027 |
| 9 | Mon 03/01/2027 | Sun 03/07/2027 |
| 10 | Mon 03/08/2027 | Sun 03/14/2027 |
| 11 | Mon 03/15/2027 | Sun 03/21/2027 |
| 12 | Mon 03/22/2027 | Sun 03/28/2027 |
| 13 | Mon 03/29/2027 | Sun 04/04/2027 |
| 14 | Mon 04/05/2027 | Sun 04/11/2027 |
| 15 | Mon 04/12/2027 | Sun 04/18/2027 |
| 16 | Mon 04/19/2027 | Sun 04/25/2027 |
| 17 | Mon 04/26/2027 | Sun 05/02/2027 |
| 18 | Mon 05/03/2027 | Sun 05/09/2027 |
| 19 | Mon 05/10/2027 | Sun 05/16/2027 |
| 20 | Mon 05/17/2027 | Sun 05/23/2027 |
| 21 | Mon 05/24/2027 | Sun 05/30/2027 |
| 22 | Mon 05/31/2027 | Sun 06/06/2027 |
| 23 | Mon 06/07/2027 | Sun 06/13/2027 |
| 24 | Mon 06/14/2027 | Sun 06/20/2027 |
| 25 | Mon 06/21/2027 | Sun 06/27/2027 |
| 26 | Mon 06/28/2027 | Sun 07/04/2027 |
| 27 | Mon 07/05/2027 | Sun 07/11/2027 |
| 28 | Mon 07/12/2027 | Sun 07/18/2027 |
| 29 | Mon 07/19/2027 | Sun 07/25/2027 |
| 30 | Mon 07/26/2027 | Sun 08/01/2027 |
| 31 | Mon 08/02/2027 | Sun 08/08/2027 |
| 32 | Mon 08/09/2027 | Sun 08/15/2027 |
| 33 | Mon 08/16/2027 | Sun 08/22/2027 |
| 34 | Mon 08/23/2027 | Sun 08/29/2027 |
| 35 | Mon 08/30/2027 | Sun 09/05/2027 |
| 36 | Mon 09/06/2027 | Sun 09/12/2027 |
| 37 | Mon 09/13/2027 | Sun 09/19/2027 |
| 38 | Mon 09/20/2027 | Sun 09/26/2027 |
| 39 | Mon 09/27/2027 | Sun 10/03/2027 |
| 40 | Mon 10/04/2027 | Sun 10/10/2027 |
| 41 | Mon 10/11/2027 | Sun 10/17/2027 |
| 42 | Mon 10/18/2027 | Sun 10/24/2027 |
| 43 | Mon 10/25/2027 | Sun 10/31/2027 |
| 44 | Mon 11/01/2027 | Sun 11/07/2027 |
| 45 | Mon 11/08/2027 | Sun 11/14/2027 |
| 46 | Mon 11/15/2027 | Sun 11/21/2027 |
| 47 | Mon 11/22/2027 | Sun 11/28/2027 |
| 48 | Mon 11/29/2027 | Sun 12/05/2027 |
| 49 | Mon 12/06/2027 | Sun 12/12/2027 |
| 50 | Mon 12/13/2027 | Sun 12/19/2027 |
| 51 | Mon 12/20/2027 | Sun 12/26/2027 |
| 52 | Mon 12/27/2027 | Sun 01/02/2028 |