UTF-8 BOM Adder
Add UTF-8 BOM to text files for Excel compatibility and fix Excel encoding issues
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Upload Text File
Drag and drop your text file here (CSV, TXT, etc.), or click to browse
Supported formats: CSV, TXT, TSV, and other text files
Maximum file size: 50MB
What is UTF-8 BOM?
UTF-8 BOM (Byte Order Mark) is a special character sequence (EF BB BF in hexadecimal) placed at the beginning of text files to identify the file as UTF-8 encoded. While optional in the UTF-8 specification, many Windows applications like Microsoft Excel require the BOM to correctly interpret UTF-8 files.
When to Use This Tool
Use this tool when opening CSV files in Excel shows garbled characters, when exporting data with international characters, when working with multi-language datasets, or when preparing CSV files for Excel import that contain special characters, accents, Chinese, Japanese, or other Unicode text.
How It Works
Simply upload your text file (CSV, TXT, TSV, etc.), and the tool adds the three-byte UTF-8 BOM sequence (0xEF, 0xBB, 0xBF) to the beginning of your file. The rest of your file content remains completely unchanged. Download the enhanced file and open it in Excel - your special characters will display correctly!
Our professional UTF-8 BOM Adder is the essential solution for adding Byte Order Mark (BOM) to text files, particularly CSV files that need to be opened correctly in Microsoft Excel. The UTF-8 BOM (EF BB BF) is a three-byte sequence placed at the beginning of text files to signal UTF-8 encoding to applications like Excel, ensuring proper display of special characters, accents, and international characters.
This tool is perfect for fixing CSV files that show garbled text or incorrect characters when opened in Excel. Simply upload your text file, and the tool adds the UTF-8 BOM signature automatically. The BOM ensures Excel recognizes the file as UTF-8 encoded, preventing common encoding issues with special characters, Chinese characters, Japanese text, accented letters, and Unicode symbols. Essential for data analysts, developers, and anyone working with international data in spreadsheet applications.
All processing happens entirely in your browser using client-side JavaScript, ensuring your sensitive data never leaves your device. This provides maximum security and privacy - no files are uploaded to our servers, and no data is stored or transmitted. The tool maintains original file content, line breaks, delimiters, and formatting while adding only the three-byte BOM header. Perfect for CSV exports, database dumps, data migration, Excel imports, and international data handling. Completely free to use with no registration required. Mobile-responsive interface works on desktop, tablet, and smartphone browsers.