The following is taken from "The Overview of the Extended Essay" in the Extended Essay Guide: Online, (2016):
Key features of the extended essay
A note for students writing in Chinese, Korean and Japanese:
Students writing their extended essay in Japanese, Korean or Chinese should use the following conversions.
• Japanese: 1 word = approximately 2 Japanese characters (upper limit 8,000 characters)
• Korean: 1 word = 1 word
• Chinese: 1 word = approximately 1.2 Chinese characters (upper limit 4,800 characters)
When typing in Chinese, Korean or Japanese word processing software is likely to include the number of characters and punctuation in the word count. Students are asked to not include punctuation in the word count for assessed work. The word count should only take into account the number of characters typed.
(Extended essay guide, p. 83)