What Is a Week Number?
A week number represents the specific week of the year, from week 1 to week 52 (or 53).
In the ISO 8601 calendar format, weeks start with Monday and end on Sunday. Monday is the first day of each week, while Sunday is the seventh day. According to this week numbering system, the first week of the year is the week containing the first Thursday of the year. This means Week 1 begins on the first Monday before or after that Thursday.
Since a year has 365 days (366 in leap years), some years include a 53rd week. This happens when January 1 falls on a Thursday in a regular year, or on a Wednesday or Thursday in a leap year.
What Is the Week Number Page?
On this page, you can do many operations related to weeks:
- View the current week no, its date range, and how many weeks left in this year.
- Find the number of the week for a specific date.
- See the date range for any week in a specific year.
Note: The page updates every minute to provide you with the most accurate information. If you check our online clock page and observe when the clock hits 00:00 on Monday (the beginning of the new week), you will see that the numbers here will update within a minute.
How to Use This Tool
The page currently offers three operations.
Find out the current week number
- Switch to "Current Week Number" tab, which is the default tab when you visit the page.
- You will see the number of the week and its corresponding date range.
- You can also see how many weeks are left in this year.
Convert date to week number
- Switch to "Date to Week Number" tab.
- Click the "Date" input to open the calendar and select a date.
- Click the "Convert to Week Number" button.
- You will see the number of the week that corresponds to your selected date.
Convert week number to date
- Switch to "Week Number to Date" tab.
- Enter the number of the week for conversion (1 for first week, up to 53)
- Enter the year (defaults to current year).
- Click the "Convert to Date" button.
- You will see the date range for your selected week.