2026 has 53 ISO weeks. It begins on a Thursday, and a year has 53 weeks when 1 January is a Thursday, or a Wednesday in a leap year. The extra week comes at the end of the year.
ISO 8601 numbers the weeks of a year from 1 to 52 or 53. Weeks run from Monday to Sunday, and week 1 is the week that holds the first Thursday of the year, which is also the week that contains 4 January. Each week belongs to the year that contains its Thursday.
Questions
Good to know
How many weeks are there in 2026?
2026 has 53 ISO weeks (52 or 53 in any year).
When does week 1 of 2026 start?
Week 1 of 2026 runs Mon, 29 Dec 2025 – Sun, 4 Jan 2026. It is the week that contains 4 January 2026.
Which years after 2026 have 53 weeks?
2032, 2037, 2043, 2048. A year has 53 ISO weeks when 1 January is a Thursday, or a Wednesday in a leap year.
How do I get a printable list or calendar?
Use the print button above for this list of weeks, or open the printable calendar of your country: it marks the public holidays and shows the ISO week number of every week.