Week numbers 2026 and 2027
Week numbers for the current year and the next: a page for each year lists every ISO calendar week with its Monday and Sunday dates and the months it spans, and marks the week you are in. Every date is computed from the ISO 8601 week rules, not typed in by hand.
Want the week for one date, today's week, or the dates of a week in another year? Use the week number calculator.
Week numbers by year
| Year | 1 January falls on | ISO weeks | Week 1 starts | Last week ends |
|---|---|---|---|---|
| 2026 | Thursday | 53 | 29 December 2025 | 3 January 2027 |
| 2027 | Friday | 52 | 4 January 2027 | 2 January 2028 |
- Week numbers 202653 weeks, from 29 December 2025 to 3 January 2027
- Week numbers 202752 weeks, from 4 January 2027 to 2 January 2028
- Week number calculatorToday's week, the week of any date, the dates of any week
How these pages count weeks
Weeks start on Monday and week 1 is the week with the first Thursday of January, as ISO 8601 defines it. That rule gives most years 52 weeks and some years 53. The first days of January can belong to the last week of the previous year, and the last days of December to week 1 of the next, so each page shows the week-year next to the week number. Calendars that start the week on Sunday count differently; each year page explains the difference for that year, and the calculator shows both numbers.
Related: count working days to a deadline with the business days calculator, or add up a week's hours with the work hours calculator.