What Week: Week 53
Find the calendar dates covered by any ISO week number.
ISO Week 53 of 2026 runs from December 28 to January 3, 2027, spanning two calendar months, with roughly -1 ISO weeks remaining in the year after it. ISO 8601 weeks always run Monday through Sunday and belong to the year containing that week's Thursday, which is why the first few days of January sometimes belong to the final week of the previous year. New Year's Eve, the End of the Year fall within this week in 2026. Next year, 2027, the same week number runs from January 3 to January 9, 2028 instead, since the exact dates shift slightly every year.
As of October 1, 2026, 12:19 PM (America/New York).
Position in the Year
Week 53 falls in the second half of the year, roughly 102% of the way through 2026's 52-53 ISO weeks.
Quarter Overlap
This week sits in calendar Q4, based on its Monday (December 28).