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The WEEKNUM function in Excel is a useful tool for determining the week number of a specific date. This function calculates the week number based on the ISO standard, which defines the first week of the year as the one containing at least 4 days in January. By using the WEEKNUM function, you can easily find out which week a certain date falls into, which can be helpful for organizing and analyzing data. Simply input the desired date into the function and it will return the corresponding week number. This feature is particularly useful for businesses and individuals who need to track and plan tasks on a weekly basis.
This article describes the formula syntax and usage of the WEEKNUM function
in Microsoft Excel.
Description
Returns the week number of a specific date. For example, the week containing January 1 is the first week of the year, and is numbered week 1.
There are two systems used for this function:
System 1 The week containing January 1 is the first week of the year, and is numbered week 1.
System 2 The week containing the first Thursday of the year is the first week of the year, and is numbered as week 1. This system is the methodology specified in ISO 8601, which is commonly known as the European week numbering system.
Syntax
WEEKNUM(serial_number,[return_type])
The WEEKNUM function syntax has the following arguments:
Serial_number Required. A date within the week. Dates should be entered by using the DATE function, or as results of other formulas or functions. For example, use DATE(2008,5,23) for the 23rd day of May, 2008. Problems can occur if dates are entered as text.
Return_type Optional. A number that determines on which day the week begins. The default is 1.
Return_type | Week begins on | System |
|---|---|---|
1 or omitted | Sunday | 1 |
2 | Monday | 1 |
11 | Monday | 1 |
12 | Tuesday | 1 |
13 | Wednesday | 1 |
14 | Thursday | 1 |
15 | Friday | 1 |
16 | Saturday | 1 |
17 | Sunday | 1 |
21 | Monday | 2 |
Remark
Excel stores dates as sequential serial numbers so they can be used in calculations. By default, January 1, 1900 is serial number 1. January 1, 2008 is serial number 39448 because it is 39,448 days after January 1, 1900.
If Serial_number is out of range for the current date base value, a #NUM! error is returned.
If Return_type is out of the range specified in the table above, a #NUM! error is returned.
Cite this article
stats writer (2024). How can I use the WEEKNUM function in Excel to determine the week number of a specific date?. PSYCHOLOGICAL SCALES. Retrieved from https://scales.arabpsychology.com/stats/how-can-i-use-the-weeknum-function-in-excel-to-determine-the-week-number-of-a-specific-date/
stats writer. "How can I use the WEEKNUM function in Excel to determine the week number of a specific date?." PSYCHOLOGICAL SCALES, 1 Jul. 2024, https://scales.arabpsychology.com/stats/how-can-i-use-the-weeknum-function-in-excel-to-determine-the-week-number-of-a-specific-date/.
stats writer. "How can I use the WEEKNUM function in Excel to determine the week number of a specific date?." PSYCHOLOGICAL SCALES, 2024. https://scales.arabpsychology.com/stats/how-can-i-use-the-weeknum-function-in-excel-to-determine-the-week-number-of-a-specific-date/.
stats writer (2024) 'How can I use the WEEKNUM function in Excel to determine the week number of a specific date?', PSYCHOLOGICAL SCALES. Available at: https://scales.arabpsychology.com/stats/how-can-i-use-the-weeknum-function-in-excel-to-determine-the-week-number-of-a-specific-date/.
[1] stats writer, "How can I use the WEEKNUM function in Excel to determine the week number of a specific date?," PSYCHOLOGICAL SCALES, vol. X, no. Y, ص Z-Z, July, 2024.
stats writer. How can I use the WEEKNUM function in Excel to determine the week number of a specific date?. PSYCHOLOGICAL SCALES. 2024;vol(issue):pages.