What is an AI readability checker?
An AI readability checker judges how easy a text is to read for a particular audience and tells you what to change. You choose the intended reader, General public, Students, Professionals or Children, and paste the text. A language model returns an estimated US grade level, whether that suits the reader and why, the longest or hardest sentences quoted back, complex words and jargon each paired with a plainer alternative, a simplified rewrite of the first paragraph, and five specific suggestions.
This is different from a formula such as Flesch-Kincaid, which counts syllables and sentence length and produces an exact number. A formula cannot tell you that "paradigm" is jargon for a general reader but normal for an academic one, or suggest a replacement. The model can, and the audience setting is what makes that judgement possible. The trade-off is that its grade level is an estimate, not a calculation, so do not report it as a measured score.
The sample on the page is a single sentence built from "notwithstanding the aforementioned considerations" and "operational paradigms". A good report quotes it as the hardest sentence, offers "however" and "ways of working" as plainer words, and rewrites it into something like "Before we use the new method, we need to rethink how teams share resources."
The check runs on the Toolz server. Your text is sent over HTTPS, the server builds the prompt and runs Gemma 3 1B, a small open model from Google, with Ollama, and the report streams back as it is written. Your draft is used to write the report and then discarded: it is not stored or logged, not used to train any model, and not sent to any third-party AI company. A 1B model can misjudge a sentence or suggest a plainer word that shifts the meaning, so read suggestions before applying them. Each check takes up to 8,000 characters, so check long documents in sections.
It is free with no signup, within about 20 checks per 10 minutes. For a numeric score, pair it with a formula-based counter; for writing that must be accessible, plain-language guidance such as the US federal plainlanguage.gov guidelines is the reference to follow.
How to check the readability of your text
Choose the intended reader
General public, Students, Professionals or Children. The same paragraph can be right for professionals and too hard for the public.
Paste your text
A web page, a policy, a report section or a school handout. A few paragraphs gives the model enough to judge.
Press Check readability
The report streams in with the grade level first, usually within a few seconds.
Apply the suggestions
Swap the jargon, split the quoted long sentences, compare with the simplified rewrite, then recheck. Copy or download the report as .txt.
What the readability report covers
Grade level for your reader
An estimated US grade level and a verdict on whether it fits the audience you chose.
Hardest sentences quoted
The longest or most tangled sentences are pulled out, so you know where to start editing.
Jargon with replacements
Each complex word comes with a plainer alternative instead of only a warning.
A simplified rewrite
The first paragraph is rewritten in plainer language as a model for the rest of the text, followed by five concrete suggestions.
Frequently Asked Questions
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