Week numbers 2025
All 52 ISO weeks of 2025 with their date ranges, alongside the US numbering for the same weeks. Under ISO 8601, week 1 of 2025 begins on 30 Dec 2024.
| Week | ISO 8601 (Monday start) | US (Sunday start) |
|---|---|---|
| 1 | 30 Dec to 5 Jan | 29 Dec to 4 Jan |
| 2 | 6 Jan to 12 Jan | 5 Jan to 11 Jan |
| 3 | 13 Jan to 19 Jan | 12 Jan to 18 Jan |
| 4 | 20 Jan to 26 Jan | 19 Jan to 25 Jan |
| 5 | 27 Jan to 2 Feb | 26 Jan to 1 Feb |
| 6 | 3 Feb to 9 Feb | 2 Feb to 8 Feb |
| 7 | 10 Feb to 16 Feb | 9 Feb to 15 Feb |
| 8 | 17 Feb to 23 Feb | 16 Feb to 22 Feb |
| 9 | 24 Feb to 2 Mar | 23 Feb to 1 Mar |
| 10 | 3 Mar to 9 Mar | 2 Mar to 8 Mar |
| 11 | 10 Mar to 16 Mar | 9 Mar to 15 Mar |
| 12 | 17 Mar to 23 Mar | 16 Mar to 22 Mar |
| 13 | 24 Mar to 30 Mar | 23 Mar to 29 Mar |
| 14 | 31 Mar to 6 Apr | 30 Mar to 5 Apr |
| 15 | 7 Apr to 13 Apr | 6 Apr to 12 Apr |
| 16 | 14 Apr to 20 Apr | 13 Apr to 19 Apr |
| 17 | 21 Apr to 27 Apr | 20 Apr to 26 Apr |
| 18 | 28 Apr to 4 May | 27 Apr to 3 May |
| 19 | 5 May to 11 May | 4 May to 10 May |
| 20 | 12 May to 18 May | 11 May to 17 May |
| 21 | 19 May to 25 May | 18 May to 24 May |
| 22 | 26 May to 1 Jun | 25 May to 31 May |
| 23 | 2 Jun to 8 Jun | 1 Jun to 7 Jun |
| 24 | 9 Jun to 15 Jun | 8 Jun to 14 Jun |
| 25 | 16 Jun to 22 Jun | 15 Jun to 21 Jun |
| 26 | 23 Jun to 29 Jun | 22 Jun to 28 Jun |
| 27 | 30 Jun to 6 Jul | 29 Jun to 5 Jul |
| 28 | 7 Jul to 13 Jul | 6 Jul to 12 Jul |
| 29 | 14 Jul to 20 Jul | 13 Jul to 19 Jul |
| 30 | 21 Jul to 27 Jul | 20 Jul to 26 Jul |
| 31 | 28 Jul to 3 Aug | 27 Jul to 2 Aug |
| 32 | 4 Aug to 10 Aug | 3 Aug to 9 Aug |
| 33 | 11 Aug to 17 Aug | 10 Aug to 16 Aug |
| 34 | 18 Aug to 24 Aug | 17 Aug to 23 Aug |
| 35 | 25 Aug to 31 Aug | 24 Aug to 30 Aug |
| 36 | 1 Sep to 7 Sep | 31 Aug to 6 Sep |
| 37 | 8 Sep to 14 Sep | 7 Sep to 13 Sep |
| 38 | 15 Sep to 21 Sep | 14 Sep to 20 Sep |
| 39 | 22 Sep to 28 Sep | 21 Sep to 27 Sep |
| 40 | 29 Sep to 5 Oct | 28 Sep to 4 Oct |
| 41 | 6 Oct to 12 Oct | 5 Oct to 11 Oct |
| 42 | 13 Oct to 19 Oct | 12 Oct to 18 Oct |
| 43 | 20 Oct to 26 Oct | 19 Oct to 25 Oct |
| 44 | 27 Oct to 2 Nov | 26 Oct to 1 Nov |
| 45 | 3 Nov to 9 Nov | 2 Nov to 8 Nov |
| 46 | 10 Nov to 16 Nov | 9 Nov to 15 Nov |
| 47 | 17 Nov to 23 Nov | 16 Nov to 22 Nov |
| 48 | 24 Nov to 30 Nov | 23 Nov to 29 Nov |
| 49 | 1 Dec to 7 Dec | 30 Nov to 6 Dec |
| 50 | 8 Dec to 14 Dec | 7 Dec to 13 Dec |
| 51 | 15 Dec to 21 Dec | 14 Dec to 20 Dec |
| 52 | 22 Dec to 28 Dec | 21 Dec to 27 Dec |
See it on a calendar. Open the week calendar for three years of week rows side by side, with your own leave, travel and deadlines marked on them. Free, no sign-up.
Why two systems disagree
Everyone agrees a year has weeks. Nobody agrees which one is week 1, and that is where the two numbers come from.
ISO 8601, used across Europe and by most software, starts weeks on Monday and gives week 1 to the first week with four or more of its days in the new year. That is usually described as "the week containing the first Thursday", which is the same rule said differently: Thursday is the fourth day of a Monday-start week.
The US convention starts weeks on Sunday and gives week 1 to whatever week holds 1 January. It is easier to explain and it produces a 53rd week far more often.
The two can differ by a full week for the same date, which is exactly the sort of thing that goes unnoticed until two reports disagree at a year end.
Other years: 2024 · 2026 · 2027 · 2028 · 2029 · what week is it now