ISO week dates
When Is Week 53? Dates & Calendar
Today: · Eastern Time (America/New_York)
Week 53 dates
Week 53 of 2026
Week 53 of 2026 runs from Monday, December 28, 2026 through Sunday, January 3, 2027.
- Relevant ISO year
- 2026
- Weeks in this ISO year
- 53
- Today’s ISO week / year
- 43 / 2026
Week 53 of 2026
Each of the seven selected dates is labeled Week 53.
December 2026
| Mon | Tue | Wed | Thu | Fri | Sat | Sun |
|---|---|---|---|---|---|---|
| Week 53 | Week 53 | Week 53 | Week 53 |
January 2027
| Mon | Tue | Wed | Thu | Fri | Sat | Sun |
|---|---|---|---|---|---|---|
| Week 53 | Week 53 | Week 53 | ||||
Week 53 by ISO year
| ISO year | Monday — start | Sunday — end |
|---|---|---|
| 2024 | Does not exist | Does not exist |
| 2025 | Does not exist | Does not exist |
| 2026 | Mon, Dec 28, 2026 | Sun, Jan 3, 2027 |
| 2027 | Does not exist | Does not exist |
| 2028 | Does not exist | Does not exist |
| 2029 | Does not exist | Does not exist |
| 2030 | Does not exist | Does not exist |
| 2031 | Does not exist | Does not exist |
| 2032 | Mon, Dec 27, 2032 | Sun, Jan 2, 2033 |
| 2033 | Does not exist | Does not exist |
| 2034 | Does not exist | Does not exist |
Quick answers
- How many weeks are in 2026?
- 2026 has 53 ISO weeks. Week 53 does not occur every year.
- What week is it today?
- Today is in ISO week 43 of 2026.
How this is calculated
- ISO weeks run Monday through Sunday. Week 1 contains January 4 (the first Thursday of the year).
- The relevant year is the ISO week-year of today in Eastern Time (America/New_York). Near New Year, it can differ from the calendar year.
- An ISO year has 52 or 53 weeks. Week 53 exists only in applicable ISO years; it is never rolled into Week 1.