Week Number 51 (Week 51) 2021

Updated on by Michael Mühl

Week Number 51 of the current year 2021 is defined as follows:

European and Asian calculation

Mainly in Europe and Asia, the international ISO 8601 definition is used for counting calendar weeks:

Week Number 51/2021

Monday, December 20, 2021

Sunday, December 26, 2021

ISO: 2021‑W51

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:

Week Number 51/2021

Sunday, December 12, 2021

Saturday, December 18, 2021

The date of the calendar Week 51 (Week 51) in the past and coming 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 51End of Week 51ISO Name
2011 European Monday, December 19, 2011Sunday, December 25, 20112011‑W51
American Sunday, December 11, 2011Saturday, December 17, 2011-
2012 European Monday, December 17, 2012Sunday, December 23, 20122012‑W51
American Sunday, December 16, 2012Saturday, December 22, 2012-
2013 European Monday, December 16, 2013Sunday, December 22, 20132013‑W51
American Sunday, December 15, 2013Saturday, December 21, 2013-
2014 European Monday, December 15, 2014Sunday, December 21, 20142014‑W51
American Sunday, December 14, 2014Saturday, December 20, 2014-
2015 European Monday, December 14, 2015Sunday, December 20, 20152015‑W51
American Sunday, December 13, 2015Saturday, December 19, 2015-
2016 European Monday, December 19, 2016Sunday, December 25, 20162016‑W51
American Sunday, December 11, 2016Saturday, December 17, 2016-
2017 European Monday, December 18, 2017Sunday, December 24, 20172017‑W51
American Sunday, December 17, 2017Saturday, December 23, 2017-
2018 European Monday, December 17, 2018Sunday, December 23, 20182018‑W51
American Sunday, December 16, 2018Saturday, December 22, 2018-
2019 European Monday, December 16, 2019Sunday, December 22, 20192019‑W51
American Sunday, December 15, 2019Saturday, December 21, 2019-
2020 European Monday, December 14, 2020Sunday, December 20, 20202020‑W51
American Sunday, December 13, 2020Saturday, December 19, 2020-
2021 European Monday, December 20, 2021Sunday, December 26, 20212021‑W51
American Sunday, December 12, 2021Saturday, December 18, 2021-
2022 European Monday, December 19, 2022Sunday, December 25, 20222022‑W51
American Sunday, December 11, 2022Saturday, December 17, 2022-
2023 European Monday, December 18, 2023Sunday, December 24, 20232023‑W51
American Sunday, December 17, 2023Saturday, December 23, 2023-
2024 European Monday, December 16, 2024Sunday, December 22, 20242024‑W51
American Sunday, December 15, 2024Saturday, December 21, 2024-
2025 European Monday, December 15, 2025Sunday, December 21, 20252025‑W51
American Sunday, December 14, 2025Saturday, December 20, 2025-
2026 European Monday, December 14, 2026Sunday, December 20, 20262026‑W51
American Sunday, December 13, 2026Saturday, December 19, 2026-
2027 European Monday, December 20, 2027Sunday, December 26, 20272027‑W51
American Sunday, December 12, 2027Saturday, December 18, 2027-
2028 European Monday, December 18, 2028Sunday, December 24, 20282028‑W51
American Sunday, December 10, 2028Saturday, December 16, 2028-
2029 European Monday, December 17, 2029Sunday, December 23, 20292029‑W51
American Sunday, December 16, 2029Saturday, December 22, 2029-
2030 European Monday, December 16, 2030Sunday, December 22, 20302030‑W51
American Sunday, December 15, 2030Saturday, December 21, 2030-
2031 European Monday, December 15, 2031Sunday, December 21, 20312031‑W51
American Sunday, December 14, 2031Saturday, December 20, 2031-

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 September 27, 2021

The pages of the "Week Numbers" category were last editorially reviewed by Michael Mühl on September 27, 2021. They all correspond to the current status.

Previous changes on June 25, 2020