Week 1 in 2021
Week 1 of 2021 begins on January 4, 2021 and ends on January 10, 2021. It covers days 4 to 10 of the year and falls in quarter 1.
Weeks since this week: 301
Week 1 of 2021 at a glance
| Starts (Monday) | January 4, 2021 |
|---|---|
| Ends (Sunday) | January 10, 2021 |
| US week (Sunday to Saturday) | 2 (January 3, 2021) |
| Month | January |
| Quarter | Q1 |
| Days of the year | 4–10 |
| Year completed at the end of this week | 2.7% |
| Weeks left in 2021 after this week | 51 |
| Weeks in 2021 | 52 |
| Even or odd week | Odd |
Calendar for January 2021
Download Calendar in printable A4 PDF
(US version) (EU/ISO Version)
All Weeks in 2021:
Past & Future Week Number 1:
US and ISO week numbers
In the US system, where weeks start on Sunday and week 1 is the week that contains 1 January, this is week 2 of 2021. It runs from January 3, 2021 to January 9, 2021.
Even and odd weeks
Week 1 is an odd week. Even and odd week numbers are used for alternating schedules such as shift rotas, school timetables, custody arrangements and waste collection.
Week 1 in other years
| From | To | |
|---|---|---|
| Week 1 in 2019 | December 31, 2018 | January 6, 2019 |
| Week 1 in 2020 | December 30, 2019 | January 5, 2020 |
| Week 1 in 2022 | January 3, 2022 | January 9, 2022 |
| Week 1 in 2023 | January 2, 2023 | January 8, 2023 |
How week numbers are counted
Most of the world numbers weeks according to the ISO 8601 standard. A week starts on Monday, and week 1 is the week that contains the first Thursday of the year, which is always the week that contains 4 January.
Week 1 of 2021 began on January 4, 2021. 2021 has 52 ISO weeks.
Because of this rule, the first days of January can belong to the last week of the previous year, and the last days of December can belong to week 1 of the next year.
In the United States, weeks usually start on Sunday and week 1 is the week that contains 1 January, so the US week number can differ from the ISO week number.
Find the week number of a date
Frequently Asked Questions (FAQ)
When does week 1 of 2021 start and end?
Week 1 of 2021 starts on January 4, 2021 and ends on January 10, 2021 (ISO 8601, Monday to Sunday).
Which month is week 1 of 2021 in?
Week 1 of 2021 is in January.
What dates are in week 1 of 2021?
January 4, 2021, January 5, 2021, January 6, 2021, January 7, 2021, January 8, 2021, January 9, 2021, and January 10, 2021
How many weeks does 2021 have?
2021 has 52 ISO weeks.
Is week 1 an even or odd week?
Week 1 is an odd week.
What is the US week number for this week?
In the US system, where weeks start on Sunday and week 1 is the week that contains 1 January, this is week 2 of 2021. It runs from January 3, 2021 to January 9, 2021.