Share via

Column data in cvs automatically converts to scientific notation

Amber Owens 20 Reputation points
2026-06-23T16:08:28.3+00:00

My csv file automatically transform long numbers to scientific notation. I tried changing it to a number, text copy it into a notepad and repasting it and the Automatic Data Conversion toggle. None of these works. Format changes only works when the csv file is open. Once I save the csv and reopen it the number automatically changes back to scientific notation. I am on Mac with version Version 16.110 of Excel.

Microsoft 365 and Office | Excel | For business | MacOS
0 comments

Answer accepted by question author

Hendrix-C 18,160 Reputation points Microsoft External Staff Moderator
2026-06-23T16:44:34.7566667+00:00

Hi Amber,

Based on your sharing, this is an expected behavior in with Excel/CSV file on Mac. The key reason is that CSV files do not store formatting, but they only store them as plain text values separated by commas. So, when you reopen .csv file, Excel reads the plain text again an applies type conversion rules on open.

To avoid this issue, the recommended approach is to import the CSV file instead of double clicking to open it directly:

  • Go to Finder > open Excel app and create a blank workbook first
  • Go to File > Import > select "CSV file" > Import > select your csv file in the Documents folder (or any folder/location you store it) > Get Data
  • Follow the Text Import Wizard when prompted. You can check your data layout on the "Preview of selected data" pane in the bottom of Text Import Wizard.
  • When done, press Finish > Import

The csv file is not a suggested file format for regularly modification so in case you need to update the data several times, I want to recommend not saving the file in csv format but using in normal xlsx file and then export it to .csv file as the last step.

Hope this information would be helpful. If you have any questions or need further assistance, please feel free to share them in the comments on this post so I can continue to support you.    

Thank you for your understanding and cooperation. I'm looking forward to your reply.

If the answer is helpful, please click "Accept Answer" and kindly upvote it.

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Was this answer helpful?

1 person found this answer helpful.

1 additional answer

Sort by: Most helpful
Most helpful Newest Oldest
  1. Bob Jones AKA CyberTaz MVP 436.2K Reputation points
    2026-06-23T16:48:05.46+00:00

    Go to Excel> Preferences> Edit - Automatic Data Conversion then clear the check on Keep first 15 digits of long numbers and display in scientific notation.

    Alternatively, type an apostrophe before pasting.

    The Comma Separated Values file type does not support anything but the minimal amount of formatting. It's best practice to save the CSV as a .xlsx workbook or import the CSV into an existing workbook.

    Was this answer helpful?

    0 comments

Your answer

Answers can be marked as 'Accepted' by the question author and 'Recommended' by moderators, which helps users know the answer solved the author's problem.