Date → week number

December 4, 2026: What week number?

Friday, December 4, 2026ISO Week 492026-W49

ISO Week 49 runs from November 30, 2026 to December 6, 2026.

Mon30NovemberTue1DecemberWed2DecemberThu3DecemberFri4DecemberSat5DecemberSun6December
← 12-03-202612-05-2026 →

ISO vs US-style week numbers

The same date can have different week numbers

ISO weeks start on Monday. The simplified US-style system starts on Sunday and counts the week containing January 1 as Week 1.

ISO week2026-W49

November 30 – December 6, 2026

MonTueWedThuFriSatSun
Week 1 contains the first Thursday of the year.ISO guide →
US-style weekWeek 49

November 29 – December 5, 2026

SunMonTueWedThuFriSat
Week 1 contains January 1.US-style guide →
ISO weekWeek 49
US-style weekWeek 49
WeekdayFriday
QuarterQ4
Day of year338 / 365
ISO weekday5 / 7

Date context

Friday, December 4, 2026 is day 338 of 2026 and belongs to ISO Week 49.

This ISO week crosses a month boundary: it starts in November and ends in December.

Distance from today

How long until December 4, 2026?

Days59
Full weeks8
Remaining days3

December 4, 2026 is 59 days from today, equal to 8 full weeks and 3 days.