Week Number Calculator
Find the ISO week number for any date.
This week
Week 35 of 2026
Monday, August 24 – Sunday, August 30, 2026
Day 238 of 365 · 53 weeks in 2026
The weeks either side
- Week 33Aug 10 – 16
- Week 34Aug 17 – 23
- Week 35NowAug 24 – 30
- Week 36Aug 31 – Sep 6
- Week 37Sep 7 – 13
- Week 38Sep 14 – 20
Take the week numbers with you. The printable calendar has a week-number column you can switch on in the settings bar.
Printable 2026 calendarLook up any other date
Frequently Asked Questions
What is the ISO week number?
The ISO week number is defined by ISO 8601. Weeks start on Monday, and week 1 is the week containing the first Thursday of the year.
Can the ISO year differ from the calendar year?
Yes, dates in late December may belong to ISO week 1 of the next year, and dates in early January may belong to the last ISO week of the previous year.