ISO week reference
Week 51 2026: December 14–20, 2026
Exact Monday-to-Sunday dates for 2026-W51. Use this week as a calendar reference, open it in the planner, or view it in the full 2026 ISO calendar.
Week51
ISO year2026
Weekdays5
QuarterQ4
ISO reference2026-W51
Starts
Ends
Length7 days
Exact dates
Dates in week 51
ISO weeks run Monday through Sunday.
MonDec 142026
TueDec 152026
WedDec 162026
ThuDec 172026
FriDec 182026
SatDec 192026
SunDec 202026
Use this week
Open Week 51 Planner
Turn these dates into a plan
Open a private weekly planner already set to December 14–20, 2026, then add priorities, deadlines, meetings and hourly work blocks.