How to use it

Paste text into the left box. With Auto-detect on, the tool inspects the characters and sets the direction: simplified input converts to Traditional, traditional input converts to Simplified. Auto-detect only switches the direction; the variant you picked (Taiwan, Hong Kong or Standard) stays as it is. The row above the two boxes shows the direction, for example Simplified → Traditional, and the ⇄ button under the arrow reverses it. The variant list (Taiwan with vocabulary, Taiwan, Hong Kong, Standard) applies to the Traditional side only, and your choice stays when the direction flips. With no text in the box, ⇄ only flips the direction and turns auto-detect off. The converted text appears on the right; Copy puts it on your clipboard and Swap feeds the output back as input so you can compare a round trip.

Conversion dictionaries are downloaded on first use (about 1 MB for simplified-to-traditional, much less for the reverse) and then cached by your browser, so subsequent conversions are instant and work offline. Text itself is never sent anywhere.

Which direction should I pick?

For readers in Taiwan, pick Taiwan (with vocabulary); plain Taiwan keeps mainland vocabulary with Taiwan glyph forms. For Hong Kong, pick Hong Kong, which follows the HKSCS glyph standard. Standard (the OpenCC standard) is a neutral choice for classical texts or when the audience spans regions. Going the other way, Traditional → Simplified with Taiwan (with vocabulary) also converts Taiwan vocabulary back to mainland terms, which is what you want for documents destined for the mainland.

Background: two scripts, one language

Simplified characters were introduced by the People's Republic of China in 1956 and 1964 to raise literacy, reducing stroke counts of about 2,000 common characters and merging some homophones into one form. Taiwan, Hong Kong and Macau kept the traditional forms, and later standardised them separately — Taiwan's Ministry of Education standard and Hong Kong's HKSCS differ in glyph details. OpenCC, the open-source project behind this converter, was started in 2010 by Guo Yunhe (BYVoid) to do what earlier tools could not: convert phrases and regional vocabulary, not just characters, using curated dictionaries that are still maintained by the community.

Where it is used

Software localisation is the biggest use: one zh-CN string file becomes zh-TW and zh-HK variants in seconds, then a native speaker reviews the vocabulary. Publishers convert manuscripts between mainland and Taiwan editions; subtitle groups and fansub communities release both versions; e-commerce sellers localise listings for Taiwan and Hong Kong marketplaces; researchers normalise mixed-script corpora before search or analysis. Wikipedia serves each Chinese article in several variants from a single source using the same approach. If you are localising a whole product, pair this with JSON formatting for string files and the word counter to check that converted copy still fits its length limits and keep the converted text under review, since a handful of terms (especially technology and brand names) always need a human decision. To check exactly what a conversion changed, run the two versions through Text Compare.