ISO week 2026-W53

Week 53, 2026

Monday, December 28, 2026 – Sunday, January 3, 2027

ISO week 53 of 2026 (2026-W53) runs from Monday, December 28, 2026 to Sunday, January 3, 2027.

This week starts 11 weeks from now. The current week is week 42, 2026.

The 7 days of week 53

Dates in week 53, 2026
Day	Date	Day of year	US week	ISO date
Monday	December 28, 2026	362 of 365	53	2026-W53-1
Tuesday	December 29, 2026	363 of 365	53	2026-W53-2
Wednesday	December 30, 2026	364 of 365	53	2026-W53-3
Thursday	December 31, 2026	365 of 365	53	2026-W53-4
Friday	January 1, 2027	1 of 365	1	2026-W53-5
Saturday	January 2, 2027	2 of 365	1	2026-W53-6
Sunday	January 3, 2027	3 of 365	2	2026-W53-7

Week 53 at a glance

ISO code: 2026-W53 (Monday is 2026-W53-1, Sunday is 2026-W53-7)
Month: December and January
Quarter: Q4 by the ISO rule (its Thursday, December 31, is in Q4); the calendar dates span Q4 and Q1
Day of year: December 28, 2026 is day 362 of 2026; January 3, 2027 is day 3 of 2027
US week number: Monday–Thursday: US week 53 of 2026; Friday–Saturday: US week 1 of 2027; Sunday: US week 2 of 2027 (Sunday-start weeks, week 1 contains January 1)
Even or odd: Week 53 is an odd week
Weeks left: This is the last ISO week of 2026
Year progress: This week spans New Year

Holidays and key dates

Friday, January 1: New Year's Day – US federal holiday

End of the ISO year

2026 has 53 ISO weeks because January 1, 2026 is a Thursday. Week 53 exists only in these long ISO years.

January 1–3, 2027 still belong to ISO year 2026, so dates in this week can show different calendar and ISO years.

Week numbers follow ISO 8601: weeks start on Monday and week 1 contains the first Thursday of the year. US weeks start on Sunday, with week 1 containing January 1.

Questions about week 53, 2026

What are the dates of week 53 in 2026?

Week 53 of 2026 starts on Monday, December 28, 2026 and ends on Sunday, January 3, 2027.

What month is week 53 of 2026?

Week 53 falls in December and January. By the Thursday rule that ISO 8601 uses for years and quarters, it counts as a December week.

How do I get week 53 of 2026 in Excel or Google Sheets?

=ISOWEEKNUM(DATE(2026,12,28)) returns 53. To go the other way, =DATE(2026,1,4)-WEEKDAY(DATE(2026,1,4),2)+1+(53-1)*7 returns the Monday, December 28, 2026.