4 Ways to Change File Extension to Uppercase/Lowercase in Windows

Have you ever had a situation where you needed to change the file extension to uppercase/lowercase in Windows? Here are quick and easy steps to accomplish this task.

How to View File Extension?

In order to view the file extension in Windows Explorer (aka “My Computer” aka Windows Start menu > Computer), you need to enable the settings.

Go to Windows Explorer and press “ALT” key once which will open up menu (For older version of Windows, this menu is always visible.). Click on “Tools” menu > “Folder Options…”.

Under “View” tab, “Advanced Settings” option, uncheck the box “Hide extensions from known file types” and click “OK” button.

Option 1: Change File Extension to .bak and Change Again to Desired Extension

Within Windows Explorer, right click on the file name, click on “Rename” and change the file extension to .bak and then again change it to uppercase/lowercase.

Change file extension

In this example “.bak” extension is just an example. You may change it to any intermediate extension.

Option 2: Use Command Prompt

This advanced option is for users who know how to use Command Prompt and execute command. When using command prompt, make sure you executing this command in the desired folder.

You can use “rename” command from command prompt. For example, use the following command to change the extension in batch.

rename *.PNG *.png

This example changes upper case “PNG” extension to lowercase “png” extension.

Option 3: Specify Extension When Saving a New File

When you create a new file, at the time of saving, you can specify uppercase extension.

If that does not work, wrap the file name with extension in quote character (“). So instead of specifying abc.txt in the Save dialog box, use “abc.txt” (use quote characters around file name).

Force extension change in save as dialog

Option 4: Use “Save As” for Existing File

You can “Save As” existing file and specify the uppercase extension. Use the trick specified in #3 if extension is not retained.



6 responses to “4 Ways to Change File Extension to Uppercase/Lowercase in Windows”

  1. maestro zen Avatar
    maestro zen


  2. Quintin Avatar

    You saved me a lot of time, thank you very much!

  3. Mari S Avatar
    Mari S

    You are genius!

  4. Nimesh Avatar

    Thank you! Exactly the solution I was looking for. Well explained.

  5. Kajal Avatar

    Thank You very much Vishal Sir 🙂

  6. amit Avatar

    thanx a lot.
    ur submission gave me a better idea for batch processing
    i have done in command prompt
    just a little command

    ren *.extension1 *.extension2

    all the files can change extension/uppercase/lowercase and also no intermediate .bak change is required.

    eg: ren *.jpg *.JPG will change the case from lowercase to uppercase

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