Useful Tools
Simplified ↔ Traditional Chinese Converter
Google Translate does a great job at converting Chinese texts written in simplified Chinese characters to traditional Chinese characters (and vice versa). Simply paste the text you would like to convert and select either "Chinese (Simplified)" to convert to simplified Chinese characters, or "Chinese (Traditional)" to convert to traditional Chinese characters.
Shinjitai (新字体) ↔ Kyūjitai (舊字體) Converter
Convert a Japanese text from Shinjitai (新字体) to Kyūjitai (舊字體), and vice versa.
This tool is also available as an iOS and Android app:
Hangul-Hanja Mixed Script Converter
To convert a Korean text written only in Hangul to Hangul-Hanja mixed script, we recommend you to use this tool from the Korean Institute of Traditional Culture (傳統文化硏究會, 전통문화연구회).