Skip to content
Free Excel Tutorials
  • Home
  • Excel For Beginners
  • Excel Intermediate
  • Advanced Excel For Experts

Data Analysis

  • How To Filter Data in Excel
  • How To Create Frequency Distribution in Excel
  • How To Create Pareto Chart in Excel
  • How to create dynamic reference table name in Excel
  • How to do a t-Test in Excel?

References

  • How to get first column number in range in Excel
  • INDEX function: Description, Usage, Syntax, Examples and Explanation
  • Find closest match in Excel
  • How to use Excel TRANSPOSE Function
  • How to use Excel MATCH Function

Data Validations

  • Excel Data validation date in next 30 days
  • Excel Data validation exists in list
  • Excel Data validation allow weekday only
  • Excel Data validation require unique number
  • Excel Data validation must begin with

ISOWEEKNUM function: Description, Usage, Syntax, Examples and Explanation

by

What is ISOWEEKNUM function in Excel?

ISOWEEKNUM function is one of Date and Time functions in Microsoft Excel that returns number of the ISO week number of the year for a given date.

Syntax of ISOWEEKNUM function

ISOWEEKNUM(date)

The ISOWEEKNUM function syntax has the following arguments.

  • Date: Date is the date-time code used by Excel for date and time calculation.

ISOWEEKNUM formula explanation

  • Microsoft Excel stores dates as sequential numbers so they can be used in calculations. By default, January 1, 1900 is serial number 1, and January 1, 2008 is serial number 39448 because it is 39,448 days after January 1, 1900.
  • If the date argument is not a valid number, ISOWEEKNUM returns the #NUM! error value.
  • If the date argument is not a valid date type, ISOWEEKNUM returns the #VALUE! error value.

Example of ISOWEEKNUM function

Steps to follow:

1. Open a new Excel worksheet.

2. Copy data in the following table below and paste it in cell A1

Note: For formulas to show results, select them, press F2 key on your keyboard and then press Enter.

You can adjust the column widths to see all the data, if need be.

Date
3/9/2012
Formula Description Result
=ISOWEEKNUM(A2) Number of the week in the year that 3/9/2012 occurs, based on weeks beginning on the default, Monday (10). 10

Post navigation

Previous Post:

How to generate random date between two dates in Excel

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Learn Basic Excel

Ribbon
Workbook
Worksheets
Format Cells
Find & Select
Sort & Filter
Templates
Print
Share
Protect
Keyboard Shortcuts

Categories

  • Charts
  • Data Analysis
  • Data Validation
  • Excel Functions
    • Cube Functions
    • Database Functions
    • Date and Time Functions
    • Engineering Functions
    • Financial Functions
    • Information Functions
    • Logical Functions
    • Lookup and Reference Functions
    • Math and Trig Functions
    • Statistical Functions
    • Text Functions
    • Web Functions
  • Excel VBA
  • Excel Video Tutorials
  • Formatting
  • Grouping
  • Others

Logical Functions

  • How to return blank in place of #DIV/0! error in Excel
  • OR function Examples in Excel
  • IF with boolean logic in Excel
  • XOR function: Description, Usage, Syntax, Examples and Explanation
  • IF with wildcards in Excel

Date Time

  • DATEVALUE function: Description, Usage, Syntax, Examples and Explanation
  • MINUTE function: Description, Usage, Syntax, Examples and Explanation
  • EDATE function: Description, Usage, Syntax, Examples and Explanation
  • How to calculate most recent day of week in Excel
  • Convert date to Julian format in Excel

Grouping

  • How to randomly assign data to groups in Excel
  • Map inputs to arbitrary values in Excel
  • Group arbitrary text values in Excel
  • Calculate conditional mode with criteria in Excel
  • Map text to numbers in Excel

General

  • How to calculate percent variance in Excel
  • How to generate random number weighted probability in Excel
  • Create dynamic workbook reference to another workbook in Excel
  • How to calculate profit margin percentage in Excel
  • Find Most Frequently Occurring Word in Excel Worksheet
© 2026 xlsoffice . All Right Reserved. | Teal Smiles | Abbreviations And Their Meaning