AJ-JpnRa Tool
「AJ-JpnRa Tool」 is Japanese text readability analysis program.
... and middle school and JLPT; 学年別漢字配当表, 常用漢字.
Essential Chinese character education guideline of elementary school is called 学年別漢字配当表, has 1006 chinese characters. And middle school one has 1130 chainese characters. If you combine essential Chinese character of Elementary and Middle school, you can have the regular-use Chinese characters.
And the AJ-JpnRa Tool has the Chinese character database of JLPT also, which was built by using the questions from previous JLPT and New JLPT tests last 23 years.