What Week Number Is It?
Today is week 45 of 2026 (ISO 8601): Thursday, November 5, 2026, in the week of November 2–8, 2026.
Updated · By the YearlyCalendar.org team
Current week number
45
Monday, November 2, 2026 – Sunday, November 8, 2026
The values above update from your device's date and time zone.
Week numbers 2026
Monday-to-Sunday dates of every ISO week in 2026. The current week is marked “This week”. Week numbers for 2027 →
| Week | Starts (Mon) | Ends (Sun) | Month(s) |
|---|---|---|---|
| Week 1 | December 29, 2025 | January 4 | December – January |
| Week 2 | January 5 | January 11 | January |
| Week 3 | January 12 | January 18 | January |
| Week 4 | January 19 | January 25 | January |
| Week 5 | January 26 | February 1 | January – February |
| Week 6 | February 2 | February 8 | February |
| Week 7 | February 9 | February 15 | February |
| Week 8 | February 16 | February 22 | February |
| Week 9 | February 23 | March 1 | February – March |
| Week 10 | March 2 | March 8 | March |
| Week 11 | March 9 | March 15 | March |
| Week 12 | March 16 | March 22 | March |
| Week 13 | March 23 | March 29 | March |
| Week 14 | March 30 | April 5 | March – April |
| Week 15 | April 6 | April 12 | April |
| Week 16 | April 13 | April 19 | April |
| Week 17 | April 20 | April 26 | April |
| Week 18 | April 27 | May 3 | April – May |
| Week 19 | May 4 | May 10 | May |
| Week 20 | May 11 | May 17 | May |
| Week 21 | May 18 | May 24 | May |
| Week 22 | May 25 | May 31 | May |
| Week 23 | June 1 | June 7 | June |
| Week 24 | June 8 | June 14 | June |
| Week 25 | June 15 | June 21 | June |
| Week 26 | June 22 | June 28 | June |
| Week 27 | June 29 | July 5 | June – July |
| Week 28 | July 6 | July 12 | July |
| Week 29 | July 13 | July 19 | July |
| Week 30 | July 20 | July 26 | July |
| Week 31 | July 27 | August 2 | July – August |
| Week 32 | August 3 | August 9 | August |
| Week 33 | August 10 | August 16 | August |
| Week 34 | August 17 | August 23 | August |
| Week 35 | August 24 | August 30 | August |
| Week 36 | August 31 | September 6 | August – September |
| Week 37 | September 7 | September 13 | September |
| Week 38 | September 14 | September 20 | September |
| Week 39 | September 21 | September 27 | September |
| Week 40 | September 28 | October 4 | September – October |
| Week 41 | October 5 | October 11 | October |
| Week 42 | October 12 | October 18 | October |
| Week 43 | October 19 | October 25 | October |
| Week 44 | October 26 | November 1 | October – November |
| Week 45 | November 2 | November 8 | November |
| Week 46 | November 9 | November 15 | November |
| Week 47 | November 16 | November 22 | November |
| Week 48 | November 23 | November 29 | November |
| Week 49 | November 30 | December 6 | November – December |
| Week 50 | December 7 | December 13 | December |
| Week 51 | December 14 | December 20 | December |
| Week 52 | December 21 | December 27 | December |
| Week 53 | December 28 | January 3, 2027 | December – January |
Week numbers by year, 2020–2040
Each year links to its full week table and a printable calendar with week numbers.
| Year | ISO weeks | Week 1 starts (Mon) | Last week ends (Sun) |
|---|---|---|---|
| 2020 week numbers | 53 | ||
| 2021 week numbers | 52 | ||
| 2022 week numbers | 52 | ||
| 2023 week numbers | 52 | ||
| 2024 week numbers | 52 | ||
| 2025 week numbers | 52 | ||
| 2026 week numbers | 53 | ||
| 2027 week numbers | 52 | ||
| 2028 week numbers | 52 | ||
| 2029 week numbers | 52 | ||
| 2030 week numbers | 52 | ||
| 2031 week numbers | 52 | ||
| 2032 week numbers | 53 | ||
| 2033 week numbers | 52 | ||
| 2034 week numbers | 52 | ||
| 2035 week numbers | 52 | ||
| 2036 week numbers | 52 | ||
| 2037 week numbers | 53 | ||
| 2038 week numbers | 52 | ||
| 2039 week numbers | 52 | ||
| 2040 week numbers | 52 |
How week numbers are counted
- Weeks run Monday to Sunday. Each week gets one number and belongs to exactly one year.
- Week 1 is the week with the year's first Thursday — the same as the week containing January 4, or the first week with at least four days in the new year.
- Weeks are numbered consecutively to 52 or 53. The table above shows how many each year has.
- Dates near New Year can belong to another year. December 29–31 may be in week 1 of the next year, and January 1–3 may be in week 52 or 53 of the previous one.
Week numbers in Excel and Google Sheets
Put a date in cell A2 and use one of these formulas. The last column shows the result for Friday, January 1, 2027.
| Formula | Returns | Result for Jan 1, 2027 |
|---|---|---|
=ISOWEEKNUM(A2) | ISO 8601 week number. Excel 2013 and later, Google Sheets. | 53 |
=WEEKNUM(A2,21) | Same ISO week number (return type 21 = Monday start, first-Thursday rule). | 53 |
=WEEKNUM(A2) | Sunday-start weeks (default type 1). | 1 |
=WEEKNUM(A2,2) | Monday-start weeks counted from January 1 (not ISO). | 1 |
=YEAR(A2-WEEKDAY(A2,2)+4) | ISO week-numbering year (the year of that week's Thursday). | 2026 |
Show week numbers in your calendar app
- Outlook (classic): File > Options > Calendar, then under Display options select Show week numbers in the month view and in the Date Navigator. For ISO numbers, set First day of week to Monday and First week of year to First 4-day week on the same page.
- New Outlook for Windows: In Calendar, open the View tab > Calendar settings > Calendar > View, select Show week numbers under Calendar appearance, then Save.
- Google Calendar (web): Click the gear icon > Settings > View options and check Show week numbers. Setting Start week on to Monday makes each row one ISO week.
- Apple Calendar (Mac): Calendar > Settings > Advanced, then select Show week numbers.
- iPhone and iPad: Settings > Apps > Calendar (Settings > Calendar before iOS 18), then turn on Week Numbers.
Get the week number in code
JavaScript
// ISO 8601 week number of a Date
function isoWeek(date) {
const d = new Date(Date.UTC(date.getFullYear(), date.getMonth(), date.getDate()));
d.setUTCDate(d.getUTCDate() + 4 - (d.getUTCDay() || 7)); // Thursday of this week
const jan1 = new Date(Date.UTC(d.getUTCFullYear(), 0, 1));
return Math.ceil(((d - jan1) / 86400000 + 1) / 7);
}
isoWeek(new Date()); // current week
isoWeek(new Date(2025, 11, 31)); // 1 (months count from 0)Python
from datetime import date
year, week, weekday = date.today().isocalendar() # current ISO week
date(2025, 12, 31).isocalendar()[:2] # (2026, 1)Frequently asked questions
Why does my calendar show a different week number?
It probably uses US-style numbering, as many US calendars and the default WEEKNUM() in Excel and Google Sheets do: weeks start on Sunday, and the week containing January 1 is always week 1, even if it has only one day. That count gives 53 weeks in most years and 54 in a leap year that starts on a Saturday, such as 2028, so the same date can get a different number than in ISO 8601. Switch your app to Monday-start ISO weeks, or use ISOWEEKNUM() in spreadsheets.
Which years have 53 weeks?
Years that start on a Thursday, and leap years that start on a Wednesday: 71 of every 400 years. The table above lists them for 2020–2040; outside that range, 2004, 2009, 2015, 2043 and 2048 also have 53 weeks.
What does an ISO week date like 2027-W26-4 mean?
It is the ISO 8601 year–week–day format: the ISO year, W with the two-digit week number, and the weekday from 1 (Monday) to 7 (Sunday). 2027-W26-4 is the Thursday of week 26 of 2027 — July 1, 2027.