ISO week details

Week 40 1309: September 30–6, 1309

Week 40 starts on Monday, September 30, 1309 and ends on Sunday, October 6, 1309.

Week40
ISO year1309
StartSep 30
EndOct 6

Quick answer

Week 40 of 1309 is the seven-day ISO week from September 30, 1309 to October 6, 1309. ISO weeks always run from Monday to Sunday.

Check the current work week

Need today’s week instead? Open the current work week dashboard for the live ISO week number, Monday-to-Sunday range, business days left and Friday planning date.

Use week 40 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 40 of 1309?

The dates are September 30, 1309 through October 6, 1309.

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 40 of 1309 (Sep 30–Oct 6, 1309)” so the week-year and date range are both clear.