ISO week reference
Week 40 2026: September 28, 2026 – October 4, 2026
Exact Monday-to-Sunday dates for 2026-W40. Use this week as a calendar reference, open it in the planner, or view it in the full 2026 ISO calendar.
Week40
ISO year2026
Weekdays5
QuarterQ3
ISO reference2026-W40
Starts
Ends
Length7 days
Exact dates
Dates in week 40
ISO weeks run Monday through Sunday.
MonSep 282026
TueSep 292026
WedSep 302026
ThuOct 12026
FriOct 22026
SatOct 32026
SunOct 42026
Use this week
Open Week 40 Planner
Turn these dates into a plan
Open a private weekly planner already set to September 28, 2026 – October 4, 2026, then add priorities, deadlines, meetings and hourly work blocks.