The Weeknum function in Excel will return the week number for a given entry date.
Weeknum function: a brief
THE Weekend The function in Excel is used to return the week number According to data entry date. If the entrance is Not a valid Excel dateThe function will return a #VALUE! error. He will also return a #Num! error If the Return_type The argument is not supported. THE Return_type must be 1, 2, or between 11 and 17.
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Objective |
Value returned by the function |
|---|---|
|
Aim to return the number of the week |
The Weeknum function in Excel will return the weekly number relating to the date of entry given. |
Weeknum function: a syntax
=WEEKNUM(serial_number, [return_type])
- serial_number: The date you want to find the week number.
- Return_type: A number that determines the day the week begins. It is optional. By default, Excel assumes Sunday as a value 1.
The following is the differences between the Weeknum and ISOWEEKNUM is,
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Weeknum function |
ISOWEEKNUM function |
|---|---|
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Can start on Sunday (default) or Monday (depending on the return type) |
Always start on Monday |
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Week 1 is the week containing January 1 |
Week 1 is the first week with at least 4 days (ISO 8601 rule) |
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Varies depending on the type of return chosen (1 or 2) |
Follows the ISO 8601 international standard in a coherent manner |
Basic example of the use of the Weeknum function:
The example covers variable scenarios of the use of the Weeknum function in practical days.
In the example above, the first five entry dates are Valid Excel datesSo the Weekend The function returns correct results.
However, the date 15-13-2025 East Not a valid dateSo the Weekend The function returns a #Value! error.
For the next input, the formula used is =WEEKNUM(B10, 99). From 99 East Not a valid return_type numberThe function is supposed to return a #Num! error. Otherwise, Excel can Ignore the non -valid return and treat it as 1Then turn a normal result.
A year has around 52 or 53 weeks, depending on the jumping years. The table below contains the value of the week for the corresponding week beach.
If the year is a year of jump, then,
This Weeknum function refers different Return Types For Weeknum (), and everyone decides what day the week begins. Refer to the table below:
Use of the Weeknum function with other nested functions:
Example of explanation:
- In the first exampleTHE Weekend The function is used with the date April 10, 2025 (10-APR-2025) in cell B4. He calculates the week's number by assuming Sunday like the first day of the week and returns 15.
- In the second exampleThe formula calculates the week's number by assuming Monday Like the first day of the week. He also comes back 15 For the same date.
- In the third exampleThe formula checks if the week number is Even or strange. From 15 is an odd number, it comes back “Odd”.
- In the Fourth exampleThe formula dynamically calculates the Number of the current week based on Date of today. The result will be automatically update.
- In the Fifth exampleThe formula subtracts the current week number Since 52 to discover How many weeks stay in the year. For April 10, 2025it comes back 37 weeks remaining.
- In the Sixth exampleThe formula checks if the week falls Quartier 2. From Week 15 be between Weeks 14 and 26it comes back “Q2”.
- In the Seventh exampleThe formula adds to a quarter of the one week's period on the current date, leading May 6, 2025 (06-May 2025).
- In the eighth exampleThe formula extracts the month number From the date. Since April has been the fourth monthit comes back 4.
- In the Ninth exampleThe formula classifies the date to First semester or the Second half of the year according to his week number. April 10, 2025, falls into the First semester.
- In the tenth exampleThe formula combines the year and the week number in a personalized format like 2025-W15.
Functions used in examples:
That's it. Was this tutorial initially published on how to use the Excel Weeknum function?
