ISO week reference
Week 4 2026: January 19–25, 2026
Exact Monday-to-Sunday dates for 2026-W04. Use this week as a calendar reference, open it in the planner, or view it in the full 2026 ISO calendar.
Week4
ISO year2026
Weekdays5
QuarterQ1
ISO reference2026-W04
Starts
Ends
Length7 days
Exact dates
Dates in week 4
ISO weeks run Monday through Sunday.
MonJan 192026
TueJan 202026
WedJan 212026
ThuJan 222026
FriJan 232026
SatJan 242026
SunJan 252026
Use this week
Open Week 4 Planner
Turn these dates into a plan
Open a private weekly planner already set to January 19–25, 2026, then add priorities, deadlines, meetings and hourly work blocks.