Big5 to UTF-8 - Traditional Chinese Converter

Convert Big5 encoded Traditional Chinese text to UTF-8. Fix legacy Taiwan and Hong Kong data. Handles HKSCS extensions. Runs locally.

Input (Big5)

Drop file here or click to browse

TXT, CSV, HTML from Taiwan/HK systems

Or paste text directly:

Output (UTF-8)

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Frequently Asked Questions

Big5 is a character encoding system for Traditional Chinese characters, developed in Taiwan in 1984. It was widely used in Taiwan, Hong Kong, and Macau before Unicode became standard. Big5 encodes around 13,000 Traditional Chinese characters using a two-byte system.

Big5 is still found in legacy systems in Taiwan and Hong Kong, particularly in older databases, email archives, text files from the 1990s-2000s, and some government records. While modern systems use UTF-8, converting old Big5 data is essential for data migration and archival projects.

Big5 is used for Traditional Chinese (Taiwan, Hong Kong) while GB2312/GBK is used for Simplified Chinese (Mainland China). They encode different character sets and are incompatible. Using the wrong encoding will result in completely garbled text. Big5 characters are visually more complex than their simplified GB2312 counterparts.

UTF-8 is the universal standard that supports all languages and characters. Converting Big5 to UTF-8 ensures compatibility with modern web applications, databases, and systems. UTF-8 prevents encoding issues when sharing files internationally and is required for modern web standards.

Mojibake (文字化け) is garbled text caused by encoding mismatches. When Big5-encoded text is opened as UTF-8, ISO-8859-1, or Windows-1252, Chinese characters appear as random symbols or question marks. This tool fixes mojibake by correctly decoding Big5 and re-encoding as UTF-8.

HKSCS (Hong Kong Supplementary Character Set) is an extension to Big5 that adds 5,000+ characters for Cantonese words, place names, and people's names used in Hong Kong. This tool supports HKSCS extensions through the browser's TextDecoder API, ensuring Hong Kong-specific characters are preserved during conversion.

You can do both. Upload Big5-encoded text files directly using the file drop zone or browse button, or paste Big5-encoded text into the input field. The tool automatically decodes Big5 and converts to UTF-8, which you can then copy or download.

If your file contains Traditional Chinese characters and was created in Taiwan or Hong Kong before 2010, it's likely Big5. Try opening it in this tool - if the Chinese characters display correctly, it's Big5. If you see garbled text in other applications but correct characters here, you've found the right encoding.

Common issues include: partial encoding (files with mixed Big5 and ASCII), vendor variants (different Big5 implementations), missing HKSCS support causing question marks for Hong Kong-specific characters, and double-encoded text (Big5 mistakenly converted multiple times). This tool handles standard Big5 and HKSCS extensions properly.

Currently, this tool processes one file at a time. For batch conversion, you can process files sequentially: upload a file, download the UTF-8 version, then upload the next. The conversion is instant and happens locally in your browser, so processing multiple files is fast and your data never leaves your device.

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