How to Convert All the Lowercase File Extensions in the Current Directory to Uppercase

Use Extension Renamer to change the extensions of a group of files.

While Windows Explorer allows you to rename several files at once, it will not allow you to simultaneously change the extensions of a group of files without renaming the file names as well. To change the format of your files to all uppercase, you can use the programs Extension Renamer or Extension Changer--or batch-change file extensions in Windows' Command Prompt.

Instructions

Extension Renamer

1. Right-click "Start." Click "Open". Choose "Tools" from the menu. Click "Folder Options". Click the "View" tab. Uncheck "Hide extensions for known file types." Click "OK."

2. Download "Extension Renamer" to your computer. Double-click the file and follow the directions onscreen to complete the installation.

3. Go to "Start," then "All Programs." Click "Extension Renamer." Click "Select Directory." Browse to the folder containing the files you want to rename.

4. Select the desired folder. Click "OK." In the "from" field, type "*.*" to select all of the files in the directory. To select only a particular type of file, type "*.", followed by the file extension.

5. Hit the "Caps Lock" key to automatically type in caps. Enter the name of the file extension into the "To" field. Click "GO!" to rename all of the files.

Windows Command Prompt

1. Press "Windows" and "E" to launch Windows Explorer, then navigate to the directory containing the files you want to rename.

2. Double-click the folder to display the contents. Right-click an empty space in the right pane. Click "Open Command Window Here."

3. Type "ren *.<real extension> *.<dummy extension>" into Command Prompt. Replace "<real extension>" with the current extension attached to the list of files. Replace "<dummy extension>" with any extension other than the one attached to the files in the directory.

4. Hit "Enter." Type "ren *.<dummy extension> *.<old extension>" into Command Prompt. Replace "<dummy extension>" with the extension name you used in the last command. Replace "<old extension>" with the name of the original extension, but in uppercase characters. Command Prompt will not switch the characters over to uppercase unless you rename the extensions to something else, first.

Extension Changer

1. Download "Extension Changer" to your computer. Double-click the file to extract the contents and install the software.

2. Press "Windows" and "E" to open the file navigator. Browse to, and double-click, the directory containing the files you want to rename.

3. Highlight all of the files in the folder. To select only a specific type of file, right-click a blank space on the right pane. Point to "Sort by." Click "Type." Left-click the first file of its type, then, while holding down the "Shift" key, select the last affiliated file.

4. Right-click an empty area in Explorer's right pane. Click "Edit the Extension." Type the extension, in caps, into the "Change to" field. Click "Change."

Tips & Warnings

• If "Type" is not listed in the list of "Sort By" options, click "More." Check "Type." Click "OK."

References

• Online Tech Tips: How to Batch Change File Extensions for Windows Files
• Addictive Tips: Batch Change/Rename File Extensions in Windows

Resources

• Extension Renamer
• Extension Changer