Week Number 1 of the next year 2024 is defined as follows.
European and Asian calculation
Mainly in Europe and Asia, the international ISO 8601 definition is used for counting calendar weeks:
American calculation
In the USA, Canada and most Latin American countries, Australia, Japan, Israel, South Korea and others, the following definition of Week 1 applies:
The date of the calendar Week 1 and other years
The following table provides an overview of the calendar Week 1 for each year. The beginning of the calendar Week 1 and its end are shown according to the two most commonly used definitions of calendar weeks worldwide. The first is the international ISO standard for Week 1, referred to here as the "European" calculation method. It is mainly used in Europe and Asia. On the other hand, the "American" calculation method for weeks is listed, which is mainly used in North and South America, Australia and Japan.
| Week Number 1 | ||||
|---|---|---|---|---|
| Year |
Calculation Method | Start of Week 1 | End of Week 1 | ISO Name |
| 2021 | European | Monday, January 4, 2021 | Sunday, January 10, 2021 | 2021‑W01 |
| American | Friday, January 1, 2021 | Saturday, January 2, 2021 | - | |
| 2022 | European | Monday, January 3, 2022 | Sunday, January 9, 2022 | 2022‑W01 |
| American | Saturday, January 1, 2022 | Saturday, January 1, 2022 | - | |
| 2023 | European | Monday, January 2, 2023 | Sunday, January 8, 2023 | 2023‑W01 |
| American | Sunday, January 1, 2023 | Saturday, January 7, 2023 | - | |
| 2024 | European | Monday, January 1, 2024 | Sunday, January 7, 2024 | 2024‑W01 |
| American | Monday, January 1, 2024 | Saturday, January 6, 2024 | - | |
| 2025 | European | Monday, December 30, 2024 | Sunday, January 5, 2025 | 2025‑W01 |
| American | Wednesday, January 1, 2025 | Saturday, January 4, 2025 | - | |
| 2026 | European | Monday, December 29, 2025 | Sunday, January 4, 2026 | 2026‑W01 |
| American | Thursday, January 1, 2026 | Saturday, January 3, 2026 | - | |
| 2027 | European | Monday, January 4, 2027 | Sunday, January 10, 2027 | 2027‑W01 |
| American | Friday, January 1, 2027 | Saturday, January 2, 2027 | - | |
Determine Week 1 or other calendar weeks in the calculator
In the Calendar Week Calculator, the entry for the European ISO calendar Week 1 is preset. Of course, you can also enter other values here to determine the date of the beginning of the week or the end of the week.
Calendar Week Calculator for other years
For calendar years further back or in the future, you will find the beginning and end of the corresponding calendar week in the Calendar Week Calculator.
Source information
As source for the information in the 'Week Numbers' category, we have used in particular:
Last update on September 22, 2023
The pages of the 'Week Numbers' category were last editorially reviewed by Michael Mühl on September 22, 2023. They all correspond to the current status.
Previous changes on June 25, 2021
- Publication of the Week Number Calculator
- Editorial revision of all texts in this category