Week Number 51 of the current year 2023 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 51 applies:
The date of the calendar Week 51 and other years
The following table provides an overview of the calendar Week 51 for each year. The beginning of the calendar Week 51 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 51, 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 51 | ||||
|---|---|---|---|---|
| Year |
Calculation Method | Start of Week 51 | End of Week 51 | ISO Name |
| 2020 | European | Monday, December 14, 2020 | Sunday, December 20, 2020 | 2020‑W51 |
| American | Sunday, December 13, 2020 | Saturday, December 19, 2020 | - | |
| 2021 | European | Monday, December 20, 2021 | Sunday, December 26, 2021 | 2021‑W51 |
| American | Sunday, December 12, 2021 | Saturday, December 18, 2021 | - | |
| 2022 | European | Monday, December 19, 2022 | Sunday, December 25, 2022 | 2022‑W51 |
| American | Sunday, December 11, 2022 | Saturday, December 17, 2022 | - | |
| 2023 | European | Monday, December 18, 2023 | Sunday, December 24, 2023 | 2023‑W51 |
| American | Sunday, December 17, 2023 | Saturday, December 23, 2023 | - | |
| 2024 | European | Monday, December 16, 2024 | Sunday, December 22, 2024 | 2024‑W51 |
| American | Sunday, December 15, 2024 | Saturday, December 21, 2024 | - | |
| 2025 | European | Monday, December 15, 2025 | Sunday, December 21, 2025 | 2025‑W51 |
| American | Sunday, December 14, 2025 | Saturday, December 20, 2025 | - | |
| 2026 | European | Monday, December 14, 2026 | Sunday, December 20, 2026 | 2026‑W51 |
| American | Sunday, December 13, 2026 | Saturday, December 19, 2026 | - | |
Determine Week 51 or other calendar weeks in the calculator
In the Calendar Week Calculator, the entry for the European ISO calendar Week 51 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 April 1, 2023
The pages of the 'Week Numbers' category were last editorially reviewed by Michael Mühl on April 1, 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