Four tools over one engine: an 11,643-entry HSK 3.0 dictionary and a segmenter that reads whole words rather than single characters. They run in your browser, need no account, and nothing you paste is uploaded.
Which words in this text don't I know yet?
Paste anything Chinese and get the words back, frequency-ranked, with the ones already in your deck marked off. Add the rest in one click.
Is this text at my level?
One verdict plus the coverage curve behind it, so you can see how close the next level would get you.
How is this pronounced?
Pinyin from whole words, not single characters, so 银行 is yính áng. Tone sandhi across word boundaries is applied and shown.
Which characters carry this text?
Every character ranked by how often it appears, with the cumulative curve that shows how few of them do most of the work.
Most free Chinese utilities are stateless: you paste text, they tell you something about it, and they forget you. That is fine for a one-off conversion and useless for studying, because the question a learner actually has is not "how hard is this text" but "how hard is this text for me" — and answering that needs to know what you already know.
These tools sit on top of your review deck. Words you have saved anywhere in HSK Studio are treated as known, so the analyzer can hand you the list of words in a text that you have not met yet, and you can add them to the deck without an export and an import in between. The paid desktop tools that do this expect you to shuttle files between your flashcard program and the analyser; here they are the same program.
Everything is stored in this browser. There is no account to make and no server that sees your text.