December 29 – January 4, 2026 · 2026-W01 · ~0% through 2026
Week Details
| Week number | 1 |
| Year | 2026 |
| ISO notation | 2026-W01 |
| Start date | Monday, December 29, 2025 |
| End date | Sunday, January 4, 2026 |
| Working days | 5 (Mon–Fri) |
| Year progress | 0% |
Days in This Week
Mon Today
Dec 29 Tue Today
Dec 30 Wed Today
Dec 31 Thu Today
Jan 1 Fri Today
Jan 2 Sat Today
Jan 3 Sun Today
Jan 4 All Weeks of 2026
Week 1 in Other Years
| Year | Start | End |
|---|---|---|
| 2027 | Jan 4, 2027 | Jan 10, 2027 |
Frequently Asked Questions
What dates are in week 1 of 2026?
Week 1 of 2026 starts on Monday, December 29, 2025 and ends on Sunday, January 4, 2026. It contains 5 working days (Monday–Friday) and a 2-day weekend (Saturday–Sunday).
What is the ISO notation for week 1, 2026?
The ISO 8601 week date notation is 2026-W01. Individual days are written as 2026-W01-1 (Monday) through 2026-W01-7 (Sunday).
How far through 2026 is week 1?
Week 1 begins around day 1 of 365, which is approximately 0% through the year.