ISO week details

Week 12 2027: March 22–28, 2027

Week 12 starts on Monday, March 22, 2027 and ends on Sunday, March 28, 2027.

Week12
ISO year2027
StartMar 22
EndMar 28

Quick answer

Week 12 of 2027 is the seven-day ISO week from March 22, 2027 to March 28, 2027. ISO weeks always run from Monday to Sunday.

Use week 12 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.

FAQ

What are the dates for week 12 of 2027?

The dates are March 22, 2027 through March 28, 2027.

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 12 of 2027 (Mar 22–Mar 28, 2027)” so the week-year and date range are both clear.