How it works
- Paste your text or enter a URL — the tool pulls the main content and strips away navigation and boilerplate.
- It splits the content into sentences and words, then calculates average sentence length and flags any very long 40+ word sentences.
- It analyzes vocabulary — the share of long or complex words, average word length and lexical variety — to gauge how much jargon slows a model down.
- It assesses structure and rhythm: paragraph length, use of lists, self-contained passages, varied sentence length and whether a summary or TL;DR is present.
- The signals combine into one readability score, a Flesch Reading Ease value and a metrics table, each with a plain-language recommendation.
What it checks
- Sentence clarity — average sentence length in the ideal 12–20 word band, with penalties for very long 40+ word sentences.
- Vocabulary simplicity — the proportion of long or complex words, average word length and overall lexical variety.
- Chunkability — short paragraphs, lists and self-contained passages a model can lift as discrete chunks.
- Rhythm and directness — varied sentence length and a clear, active voice rather than dense, meandering prose.
- Summary presence — a TL;DR or summary that gives a model a ready-made condensed answer.
- Flesch Reading Ease — a standard 0–100 readability value reported alongside the full metrics table.
Why it matters
When an AI system answers a question, it doesn't read your page top to bottom — it retrieves the passages most relevant to the query and stitches them into a response. Long tangled sentences, heavy jargon and wall-of-text paragraphs make that extraction error-prone, so the model either paraphrases you inaccurately or skips your content for a clearer source. Writing that scores well here is easier for LLMs to chunk, quote and attribute correctly, which directly improves your odds of being cited in AI answers rather than misrepresented or ignored.
How to improve your score
Aim for an average sentence length of 12–20 words and break any 40+ word sentence into two. Swap complex or niche vocabulary for plainer equivalents wherever meaning allows, and keep paragraphs short — two to four sentences each. Add lists for steps and comparisons, make each passage self-contained so it reads well out of context, and open with a short summary or TL;DR. Vary your sentence length to keep rhythm natural, then re-run the tool to confirm your Flesch score and readability grade have improved.
Frequently asked questions
How is the LLM Readability Score different from Flesch Reading Ease?
Flesch Reading Ease measures human reading difficulty from sentence and word length alone. The LLM Readability Score also weighs structure, chunkability, lexical variety and summary presence — the factors that specifically affect how well a language model can parse and reuse your text.
What is a good sentence length for LLM readability?
An average of roughly 12–20 words per sentence works best. That range stays informative without becoming hard to chunk, and you should avoid very long 40+ word sentences, which are the most common cause of misquotes.
Can I score content by URL instead of pasting it?
Yes. Enter a URL and the tool fetches the page, extracts the main content and scores it as published, so you can benchmark live articles as well as unpublished drafts.