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

Data Analysis

  • Excel Pie Chart
  • How to count table columns in Excel
  • Number and Text Filters Examples in Excel
  • How to Create Gantt Chart in Excel
  • How To Perform and Interpret Regression Analysis in Excel

References

  • Find closest match in Excel
  • How to reference named range different sheet in Excel
  • How to use Excel INDIRECT Function
  • How to use Excel LOOKUP Function
  • How to get address of first cell in range in Excel

Data Validations

  • Excel Data validation require unique number
  • Excel Data validation no punctuation
  • Excel Data validation exists in list
  • Excel Data validation allow uppercase only
  • Excel Data validation must contain specific text

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Your email address will not be published.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 use Excel XOR Function
  • OR function: Description, Usage, Syntax, Examples and Explanation
  • How to use Excel FALSE Function
  • How to use Excel NOT Function
  • Return blank if in Excel

Date Time

  • Calculate days remaining in Excel
  • Add workdays to date custom weekends in Excel
  • Calculate years between dates in Excel
  • Convert text date dd/mm/yy to mm/dd/yy in Excel
  • Display Days until expiration date in Excel

Grouping

  • Calculate conditional mode with criteria in Excel
  • Map inputs to arbitrary values in Excel
  • How to randomly assign data to groups in Excel
  • Group times into 3 hour buckets in Excel
  • Categorize text with keywords in Excel

General

  • How to generate random date between two dates in Excel
  • Transpose: Switch ‘Rows to Columns’ or ‘Columns to Rows’ in Excel
  • AutoRecover file that was never saved in Excel
  • List sheet names with formula in Excel
  • How to create dynamic worksheet reference in Excel
© 2026 xlsoffice . All Right Reserved. | Teal Smiles | Abbreviations And Their Meaning