This tool converts Simplified Chinese characters to Traditional (Complex) Chinese characters and vice versa.

I have not fully tested this tool. It works on IE.The free online tools, Automatic conversion between simplified and traditional Chinese.
Current Chinese language speakers use two different writing systems ― simplified and traditional. Traditional Chinese characters are used primary in the Republic of China (Taiwan), Hong Kong, Macau, and the Chinese diaspora in North America. Simplified Chinese is used in Mainland China, Singapore, and the Chinese diaspora in Southeast Asia such as Indonesia and Malaysia.

Sample differences of Chinese writing systems