See what week of the year it is in ISO 8601 and the US system, the day of the year, how many days are left, and a table of every week of the year with start and end dates.
The tool reads the date from your device (in your time zone, so the day turns over at your midnight) and shows the week of the year in two systems, ISO 8601 as used in most of the world and the US system, plus the day of the year, the days left and a table of every week of the year with its dates.
In ISO 8601 the week starts on Monday and week 1 is the one containing the first Thursday of the year (the same as containing January 4). Because a week belongs to the year of its Thursday, the first days of January can fall in the last week of the previous year and the last days of December in week 1 of the next. An ISO year has 53 weeks when January 1 is a Thursday, or a Wednesday in a leap year; otherwise it has 52.
In the US system the week starts on Sunday and week 1 is the one containing January 1, even if it starts in December. A week belongs to the year of its Saturday, so December 31, 2027, a Friday, is already in week 1 of 2028. This is the CLDR en-US convention; other programs may number differently, so check which system your document uses.
Paste the code into your HTML and the tool shows up on your page, without J-Kit's navigation and ads. It still runs in the browser of whoever visits your site.
<iframe
src="https://jkit.tools/embed/en-US/what-week-is-it"
width="100%"
height="600"
style="border:0"
loading="lazy"
title="What Week Is It? Week Number"
></iframe>
<p style="font-size:12px;margin:6px 0 0">Tool by <a href="https://jkit.tools/en/tools/what-week-is-it">J-Kit</a></p>Using it in a paper, class or post? Copy the link or a ready-made reference. The access date is today's.
<a href="https://jkit.tools/en/tools/what-week-is-it">What Week Is It? Week Number</a>
These references help contextualize formulas, standards, APIs and limitations used on this page. They do not replace professional validation when a result has legal, financial, medical or operational impact.
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).
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 |