Week numbers 2025

2025 has 52 weeks. Week 1 starts on Monday, December 30, 2024 and week 52 ends on Sunday, December 28, 2025.

All week numbers of 2025, with the start and end date of every week, in both the ISO-8601 standard and the US system.

All weeks of 2025

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Week numbers 2025 (ISO-8601)
WeekStart dateEnd date
1Wednesday, January 1, 2025Sunday, January 5, 2025
2Monday, January 6, 2025Sunday, January 12, 2025
3Monday, January 13, 2025Sunday, January 19, 2025
4Monday, January 20, 2025Sunday, January 26, 2025
5Monday, January 27, 2025Sunday, February 2, 2025
6Monday, February 3, 2025Sunday, February 9, 2025
7Monday, February 10, 2025Sunday, February 16, 2025
8Monday, February 17, 2025Sunday, February 23, 2025
9Monday, February 24, 2025Sunday, March 2, 2025
10Monday, March 3, 2025Sunday, March 9, 2025
11Monday, March 10, 2025Sunday, March 16, 2025
12Monday, March 17, 2025Sunday, March 23, 2025
13Monday, March 24, 2025Sunday, March 30, 2025
14Monday, March 31, 2025Sunday, April 6, 2025
15Monday, April 7, 2025Sunday, April 13, 2025
16Monday, April 14, 2025Sunday, April 20, 2025
17Monday, April 21, 2025Sunday, April 27, 2025
18Monday, April 28, 2025Sunday, May 4, 2025
19Monday, May 5, 2025Sunday, May 11, 2025
20Monday, May 12, 2025Sunday, May 18, 2025
21Monday, May 19, 2025Sunday, May 25, 2025
22Monday, May 26, 2025Sunday, June 1, 2025
23Monday, June 2, 2025Sunday, June 8, 2025
24Monday, June 9, 2025Sunday, June 15, 2025
25Monday, June 16, 2025Sunday, June 22, 2025
26Monday, June 23, 2025Sunday, June 29, 2025
27Monday, June 30, 2025Sunday, July 6, 2025
28Monday, July 7, 2025Sunday, July 13, 2025
29Monday, July 14, 2025Sunday, July 20, 2025
30Monday, July 21, 2025Sunday, July 27, 2025
31Monday, July 28, 2025Sunday, August 3, 2025
32Monday, August 4, 2025Sunday, August 10, 2025
33Monday, August 11, 2025Sunday, August 17, 2025
34Monday, August 18, 2025Sunday, August 24, 2025
35Monday, August 25, 2025Sunday, August 31, 2025
36Monday, September 1, 2025Sunday, September 7, 2025
37Monday, September 8, 2025Sunday, September 14, 2025
38Monday, September 15, 2025Sunday, September 21, 2025
39Monday, September 22, 2025Sunday, September 28, 2025
40Monday, September 29, 2025Sunday, October 5, 2025
41Monday, October 6, 2025Sunday, October 12, 2025
42Monday, October 13, 2025Sunday, October 19, 2025
43Monday, October 20, 2025Sunday, October 26, 2025
44Monday, October 27, 2025Sunday, November 2, 2025
45Monday, November 3, 2025Sunday, November 9, 2025
46Monday, November 10, 2025Sunday, November 16, 2025
47Monday, November 17, 2025Sunday, November 23, 2025
48Monday, November 24, 2025Sunday, November 30, 2025
49Monday, December 1, 2025Sunday, December 7, 2025
50Monday, December 8, 2025Sunday, December 14, 2025
51Monday, December 15, 2025Sunday, December 21, 2025
52Monday, December 22, 2025Sunday, December 28, 2025
1Monday, December 29, 2025Wednesday, December 31, 2025

The first and last row of a year overview can be shorter than seven days.

Week numbers according to the international standard. Source: ISO 8601. More about our sources

The US count (weeks start on Sunday, week 1 contains 1 January) is a common convention without an official standard.

US week numbers 2025

In the United States weeks start on Sunday and week 1 is the week containing January 1 (as in Excel WEEKNUM and Outlook).

US week numbers 2025 (Sunday to Saturday)
WeekStart dateEnd date
1Wednesday, January 1, 2025Saturday, January 4, 2025
2Sunday, January 5, 2025Saturday, January 11, 2025
3Sunday, January 12, 2025Saturday, January 18, 2025
4Sunday, January 19, 2025Saturday, January 25, 2025
5Sunday, January 26, 2025Saturday, February 1, 2025
6Sunday, February 2, 2025Saturday, February 8, 2025
7Sunday, February 9, 2025Saturday, February 15, 2025
8Sunday, February 16, 2025Saturday, February 22, 2025
9Sunday, February 23, 2025Saturday, March 1, 2025
10Sunday, March 2, 2025Saturday, March 8, 2025
11Sunday, March 9, 2025Saturday, March 15, 2025
12Sunday, March 16, 2025Saturday, March 22, 2025
13Sunday, March 23, 2025Saturday, March 29, 2025
14Sunday, March 30, 2025Saturday, April 5, 2025
15Sunday, April 6, 2025Saturday, April 12, 2025
16Sunday, April 13, 2025Saturday, April 19, 2025
17Sunday, April 20, 2025Saturday, April 26, 2025
18Sunday, April 27, 2025Saturday, May 3, 2025
19Sunday, May 4, 2025Saturday, May 10, 2025
20Sunday, May 11, 2025Saturday, May 17, 2025
21Sunday, May 18, 2025Saturday, May 24, 2025
22Sunday, May 25, 2025Saturday, May 31, 2025
23Sunday, June 1, 2025Saturday, June 7, 2025
24Sunday, June 8, 2025Saturday, June 14, 2025
25Sunday, June 15, 2025Saturday, June 21, 2025
26Sunday, June 22, 2025Saturday, June 28, 2025
27Sunday, June 29, 2025Saturday, July 5, 2025
28Sunday, July 6, 2025Saturday, July 12, 2025
29Sunday, July 13, 2025Saturday, July 19, 2025
30Sunday, July 20, 2025Saturday, July 26, 2025
31Sunday, July 27, 2025Saturday, August 2, 2025
32Sunday, August 3, 2025Saturday, August 9, 2025
33Sunday, August 10, 2025Saturday, August 16, 2025
34Sunday, August 17, 2025Saturday, August 23, 2025
35Sunday, August 24, 2025Saturday, August 30, 2025
36Sunday, August 31, 2025Saturday, September 6, 2025
37Sunday, September 7, 2025Saturday, September 13, 2025
38Sunday, September 14, 2025Saturday, September 20, 2025
39Sunday, September 21, 2025Saturday, September 27, 2025
40Sunday, September 28, 2025Saturday, October 4, 2025
41Sunday, October 5, 2025Saturday, October 11, 2025
42Sunday, October 12, 2025Saturday, October 18, 2025
43Sunday, October 19, 2025Saturday, October 25, 2025
44Sunday, October 26, 2025Saturday, November 1, 2025
45Sunday, November 2, 2025Saturday, November 8, 2025
46Sunday, November 9, 2025Saturday, November 15, 2025
47Sunday, November 16, 2025Saturday, November 22, 2025
48Sunday, November 23, 2025Saturday, November 29, 2025
49Sunday, November 30, 2025Saturday, December 6, 2025
50Sunday, December 7, 2025Saturday, December 13, 2025
51Sunday, December 14, 2025Saturday, December 20, 2025
52Sunday, December 21, 2025Saturday, December 27, 2025
53Sunday, December 28, 2025Wednesday, December 31, 2025

How do week numbers work?

Most of the world uses the ISO-8601 standard: weeks start on Monday and week 1 is the week with the first Thursday of the year. A year can therefore start in week 52 or 53 of the previous year.

Week numbers in 2025: US and ISO

In the US system, 2025 is divided into 53 numbered weeks. Week 1 starts on January 1, a Wednesday, and ends on the first Saturday of the year. Every following week runs from Sunday to Saturday, and the last week ends on December 31, so the first and last weeks can be shorter than seven days.

Under ISO 8601, 2025 has 52 weeks, each running from Monday to Sunday. ISO week 1 starts on Monday, December 30, 2024.

The next year with 53 ISO weeks is 2026.

Because ISO week 1 already starts on Monday, December 30, 2024, the last days of December belong to ISO week 1 of 2025, while in the US system they are still part of the old year.

Using the 2025 week numbers

The tables above show the start and end date of every week in both systems. That makes it easy to find the dates for a week number, for a delivery, a payroll period or a project deadline, whichever system your company or partner uses.

You can print all week numbers of 2025 or download them as an Excel or PDF file.

Frequently asked questions

How many weeks are there in 2025?

2025 has 52 weeks under ISO-8601 and 53 weeks in the US system, where a new week starts every Sunday.

When does week 1 of 2025 start?

In the US system, week 1 starts on January 1. Under ISO-8601, week 1 of 2025 starts on Monday, December 30, 2024.

Can I download the 2025 week numbers?

Yes, use the buttons next to the table: print, Excel or PDF.

What day of the week does 2025 start on?

January 1, 2025 is a Wednesday. In the US system, week 1 runs from that day until the first Saturday of the year.

How many weeks are there in 2026?

Under ISO-8601, 2026 has 53 weeks.

See also

In other countries