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

Data Analysis

  • Excel Pie Chart
  • Everything about Charts in Excel
  • Calculate Conditional Percentile ‘IF’ in table in Excel
  • How to Create Column Chart in Excel
  • Data Series in Excel

References

  • Perform case-sensitive Lookup in Excel
  • Get nth match with INDEX / MATCH in Excel
  • INDEX function: Description, Usage, Syntax, Examples and Explanation
  • Lookup entire row in Excel
  • Count rows with at least n matching values

Data Validations

  • Excel Data validation exists in list
  • Excel Data validation allow uppercase only
  • Excel Data validation specific characters only
  • Excel Data validation whole percentage only
  • Excel Data validation no punctuation

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Your email address will not be published.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

  • XOR function: Description, Usage, Syntax, Examples and Explanation
  • Extract multiple matches into separate rows in Excel
  • How to use Excel XOR Function
  • IF, AND, OR and NOT Functions Examples in Excel
  • Not Equal To ‘<>‘ operator in Excel

Date Time

  • Get last weekday in month in Excel
  • How to get Weekdays, Working days between Two Dates in Excel
  • Excel Date & Time Functions Example
  • Roll back weekday to Friday base on a particular date in Excel
  • How to calculate project start date based on end date in Excel

Grouping

  • How to randomly assign data to groups in Excel
  • How to randomly assign people to groups in Excel
  • Group arbitrary text values in Excel
  • Map inputs to arbitrary values in Excel
  • Group times into unequal buckets in Excel

General

  • AutoFit Column Width, AutoFit Row Height in Excel
  • Subtotal by color in Excel
  • AutoRecover file that was never saved in Excel
  • How to calculate project complete percentage in Excel
  • 44 Practical Excel IF function Examples
© 2026 xlsoffice . All Right Reserved. | Teal Smiles | Abbreviations And Their Meaning