Week Numbers 2027

Every ISO week of the year with its Monday and Sunday – as used in business, logistics and most of Europe.

In short

2027 has 52 ISO weeks. Week 1 runs from Monday, January 4, 2027 to Sunday, January 10, 2027; the days before still belong to week 53 of 2026. ISO weeks start on Monday, while US wall calendars start on Sunday.

Week numbers 2027PDF · US Letter A4One page, portrait

All 52 weeks of 2027

Week	Monday	Sunday
1	01/04/2027	01/10/2027
2	01/11/2027	01/17/2027
3	01/18/2027	01/24/2027
4	01/25/2027	01/31/2027
5	02/01/2027	02/07/2027
6	02/08/2027	02/14/2027
7	02/15/2027	02/21/2027
8	02/22/2027	02/28/2027
9	03/01/2027	03/07/2027
10	03/08/2027	03/14/2027
11	03/15/2027	03/21/2027
12	03/22/2027	03/28/2027
13	03/29/2027	04/04/2027
14	04/05/2027	04/11/2027
15	04/12/2027	04/18/2027
16	04/19/2027	04/25/2027
17	04/26/2027	05/02/2027
18	05/03/2027	05/09/2027
19	05/10/2027	05/16/2027
20	05/17/2027	05/23/2027
21	05/24/2027	05/30/2027
22	05/31/2027	06/06/2027
23	06/07/2027	06/13/2027
24	06/14/2027	06/20/2027
25	06/21/2027	06/27/2027
26	06/28/2027	07/04/2027

Week	Monday	Sunday
27	07/05/2027	07/11/2027
28	07/12/2027	07/18/2027
29	07/19/2027	07/25/2027
30	07/26/2027	08/01/2027
31	08/02/2027	08/08/2027
32	08/09/2027	08/15/2027
33	08/16/2027	08/22/2027
34	08/23/2027	08/29/2027
35	08/30/2027	09/05/2027
36	09/06/2027	09/12/2027
37	09/13/2027	09/19/2027
38	09/20/2027	09/26/2027
39	09/27/2027	10/03/2027
40	10/04/2027	10/10/2027
41	10/11/2027	10/17/2027
42	10/18/2027	10/24/2027
43	10/25/2027	10/31/2027
44	11/01/2027	11/07/2027
45	11/08/2027	11/14/2027
46	11/15/2027	11/21/2027
47	11/22/2027	11/28/2027
48	11/29/2027	12/05/2027
49	12/06/2027	12/12/2027
50	12/13/2027	12/19/2027
51	12/20/2027	12/26/2027
52	12/27/2027	01/02/2028

Questions

How many weeks are in 2027?

52 ISO weeks. A year has 53 weeks when it starts on a Thursday (or on a Wednesday in a leap year).

What is week 1?

Under ISO 8601, week 1 is the week with the first Thursday of the year – the week that contains January 4.

Does the US use ISO week numbers?

Many US companies use them for planning, but there is no official US week numbering; some count from the week containing January 1 with Sunday as the first day.

Source: ISO 8601 week dates · Updated: November 2026 · How the calendars are made

All 52 weeks of 2027

Questions

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