How do I find the week number for a specific date?
Switch to the Date → Week mode, pick the date, and you’ll instantly see its ISO 8601 week, Canada (Sun–Sat) week, weekday, and day-of-year.
whatweek.ca
See what week of the year it is right now in Canada, including the current week number and the dates this week starts and ends.
Date ↔ Week Number Converter
Today is ISO week 20 of 2026 (Canada week 20). Use the tool below for any date between 1900 and 2100.
- ISO 8601 week
- 2026-W20 · Monday, May 11, 2026 – Sunday, May 17, 2026
- Canada week (Sun–Sat)
- Week 20 (2026) · Sunday, May 10, 2026 – Saturday, May 16, 2026
- Weekday
- Wednesday
- Day of year
- 133 / 365
Understanding Week Numbers in Canada
In Canada, two week-numbering systems often coexist. The international standard (ISO 8601) starts the week on Monday and is used universally in software, logistics, and global business. However, many Canadian institutions and personal calendars start the week on Sunday.
Our converter calculates both simultaneously. The ‘Date → Week’ mode takes a calendar date and computes both the ISO 8601 week number (Mon–Sun) and the Canada week number (Sun–Sat). It also reports the weekday and day-of-year—essential for payroll, project planning, and school schedules.
The ‘Week → Dates’ mode works the other way: enter an ISO year and week number to get the exact date range. This is the perfect tool for translating 'Week 42' delivery dates into concrete calendar days.
Frequently asked questions
How do I convert a week number into a date range?
Use the Week → Dates mode and enter the ISO year + week number. The Monday–Sunday range is shown along with the total number of ISO weeks in that year.
Why does the Canada week sometimes differ from the ISO week?
ISO 8601 weeks start on Monday; Canadian Sun–Sat weeks start on Sunday. Around January 1 and December 31, the two numbering systems can disagree by 1.
How many weeks are in 2026?
2026 contains 53 ISO weeks.