UTF-8 to UTF-8 with BOM Converter

This simple Python script allows users to convert UTF-8 text files into UTF-8 with BOM so that Windows Notepad (especially on Windows 11) correctly recognizes the encoding.

Many .txt files created or saved as UTF-8 without a BOM may be misinterpreted by Notepad as UTF-16 or another encoding, causing display issues. This tool fixes that automatically with a user-friendly GUI.

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Features

• Opens a file picker to select your UTF-8 .txt file.
• Converts the file to UTF-8 with BOM.
• Saves the output in the same folder with _utf8_bom appended to the filename.
• No command-line knowledge required — click and convert!

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Requirements

• Python 3.x
• No additional libraries needed (uses built-in tkinter and os modules).
  • tkinter comes pre-installed with standard Python distributions.

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Usage

1. Download the script utf8_add_bom.py.
2. Double-click the script to launch the GUI.
3. Select a UTF-8 .txt file.
4. The script creates a new file with _utf8_bom appended to the name in the same folder.
5. Open the new file in Notepad — it should now be correctly recognized as UTF-8.

Example:

Original file:

example.txt

Converted file:

example_utf8_bom.txt

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Converting the Script to an Executable (Optional)

If you do not want to use the prebuilt .exe provided in the GitHub release, you can create your own using PyInstaller:

1. Install PyInstaller:

pip install pyinstaller

2. Navigate to the folder containing utf8_add_bom.py and run:

pyinstaller --onefile --windowed utf8_add_bom.py

3. After it finishes, you will find the standalone executable in the dist folder:

dist\utf8_add_bom.exe

4. You can now run this .exe directly — no Python installation is required.

Optional flags:

• Add a custom icon:

pyinstaller --onefile --windowed --icon=myicon.ico utf8_add_bom.py

• Change the output folder:

pyinstaller --onefile --windowed --distpath ./output utf8_add_bom.py

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Notes

• This script does not modify the original file.
• The output file is fully compatible with Windows Notepad, preventing mojibake caused by encoding misdetection.