What date is ISO week 53 of 2026?
With no weekday given, this returns the Monday that starts the week — the convention this tool uses when a day is not specified.
Worked from a fixed input so the numbers stay put: 2026-W53. Try your own on the home page.
ISO week 53 of 2026, Monday, is 2026-12-28.
- Calendar date
- 2026-12-28
- ISO year
- 2026
- ISO week
- 53
- ISO weekday
- 1 (Monday)
- Weeks in that ISO year
- 53
No weekday given — defaulted to Monday
"2026-W53" named a week but not a day within it, so this is the Monday that starts that week.
Fix: Add "-D" with D from 1 (Monday) to 7 (Sunday) to name a specific day, e.g. "2026-W53-5" for Friday.
Other examples
Not a general calendar or scheduling tool, and it does not know about business fiscal-year or retail 4-4-5 week numbering, which are different systems that also call themselves "week numbers." It has no concept of time of day or timezone — it operates on calendar dates only. Not for US-style "week of the month" or non-ISO week-start conventions (e.g. Sunday-start week numbering used by some US calendars).