Week 21 2025: May 19–25, 2025
Week 21 starts on Monday, May 19, 2025 and ends on Sunday, May 25, 2025.
Quick answer
Week 21 of 2025 is the seven-day ISO week from May 19, 2025 to May 25, 2025. ISO weeks always run from Monday to Sunday.
Use week 21 in professional planning
This permanent week reference can be used in project plans, payroll notes, weekly reports, production schedules and deadline documents. Share the week number together with the ISO year and exact date range to avoid ambiguity around New Year.
For calculations that span more than one week, use the weeks between dates calculator. For work schedules, compare the same range with the business days calculator or open the project timeline calculator.
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FAQ
What are the dates for week 21 of 2025?
The dates are May 19, 2025 through May 25, 2025.
What day does this week start?
It starts on Monday.
What day does this week end?
It ends on Sunday.
How should I write this week in a report?
Use “ISO week 21 of 2025 (May 19–May 25, 2025)” so the week-year and date range are both clear.