About this tool
For any date, return the day-of-week name, the ISO 8601 week number, and the day-of-year (1–366).
Formula
ISO week: shift to Thursday of the same week, count weeks from year-start. Day-of-year: days since Jan 1.
Worked example
2026-05-05 → Tuesday, ISO week 19, day 125 of the year.
Notes
ISO weeks start on Monday and the first week is the one containing the first Thursday of the year.