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Session Id : SP1zuLNjm/YUt6FJkA1eDT
Power Automate - Building Flows
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Change Excel Serial Date Format for formatDateTime to ISO 8601?

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Posted on 13 Aug 2021 22:59:38 by 59

Making a flow that parses a table in an excel spreadsheet to send out an email with a list of all rows with a date that is within a month of flow execution. However after googling for hours I've finally come to realize that my problem stems from excel storing dates as serial date format. 

 

I know I need to compose an expression prior to running my comparison between formatDateTime of the spreadsheet and the current time, however all solutions I've found seem to run into different errors such as the value needing to be an array rather than a string despite converting back from string. 

 

My error is as follows:  'In function 'formatDateTime', the value provided for date time string '44389.4583333333' was not valid. The datetime string must match ISO 8601 format.'

 

Please feel free to ask any questions if necessary, this project is really important to my clients and me. I know people don't like when someone asks a question without prior research, but I have been at it for like 5 hours now. Thank you in advance for any assistance you can provide.

  • 001001100110 Profile Picture
    23 on 18 Mar 2023 at 19:21:42
    Re: Change Excel Serial Date Format for formatDateTime to ISO 8601?

    Thanks! Solved my issue!

     

  • Verified answer
    v-LilyW-msft Profile Picture
    on 18 Aug 2021 at 06:33:46
    Re: Change Excel Serial Date Format for formatDateTime to ISO 8601?

    Hi @Kongol 

    Has your problem been solved?

    As explained by @ekarim2020 ,because Excel stores dates as an integer. The integer represents the number of days that have elapsed since the 1st January, 1900. 

    So if you want to format the date time in excel and compare with current time. The DateTime Format in List rows present in a table action need to select ISO 8601.

    vLilyWmsft_1-1629267973157.png

    Then you can format the date time in excel and compare with current time.
    vLilyWmsft_0-1629267884883.png

    Hope the content above may help you.

    Best Regards

  • Ellis Karim Profile Picture
    10,927 Super User 2025 Season 1 on 14 Aug 2021 at 07:40:51
    Re: Change Excel Serial Date Format for formatDateTime to ISO 8601?

    I have had to convert excel dates earlier this week.

    This is because Excel stores dates as an integer. The integer represents the number of days that have elapsed since the 1st January, 1900.  The following post should tell you everything you need to know to solve your problem:  Easily convert Excel Dates to usable Power Automate Dates.  Note the section on Validate the Excel data first .

    Please see also: Excel Date changes in Power Automate

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    Hope this helps.

    Ellis

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