Date to Week Number
Get the ISO week number for any date
ISO Week Number
W18
2026-W18
Day of Week
Thursday
Day 4 of 7
Week Range
Mon - Sun
Apr 27, 2026
Weeks in Year
53
ISO year 2026
Week Boundaries
Week starts:Mon, Apr 27, 2026
Week ends:Sun, May 3, 2026
Week Number to Date Range
Find the date range for a specific week
Range: 1900 - 2100
Range: 1 - 53
2026-W18
Mon, Apr 27, 2026 - Sun, May 3, 2026
Days in Week 18
MonApr 27, 2026
TueApr 28, 2026
WedApr 29, 2026
ThuApr 30, 2026
FriMay 1, 2026
SatMay 2, 2026
SunMay 3, 2026
Current Week
We are currently in
Week 18 of 2026
ISO notation: 2026-W18
About ISO Week Numbers
- ISO weeks start on Monday and end on Sunday
- Week 1 is the week containing the first Thursday of the year
- A year can have 52 or 53 weeks
- December 31 might be in week 1 of the next year
- January 1 might be in week 52 or 53 of the previous year