Claude readability checker

GPTCleanup Pro's Claude readability checker reads a passage of Claude output and reports how it moves: sentence length, paragraph density, an approximate grade level, and specifically whether that level is being driven by vocabulary or by sentence architecture. It's tuned to a documented tendency in Claude's writing, nested, qualifying clauses that raise the reading level even when every individual word is plain.

It's a server tool by necessity. Text is sent to our server, read once, and the result returns to the page. 5 free checks in any rolling 24 hours, no account required.

Readability and grammar are scored separately here. Readability is a property of sentence architecture. Grammar is a property of sentence correctness. A single combined figure would obscure which one a given passage actually needs work on.

Claude's vocabulary is rarely the source of reading difficulty. The consistent finding across its output is sentence length driven by nested subordinate clauses, a caveat or an exception stated ahead of the main claim, extending the distance a reader travels before the sentence resolves.

That is distinct from vocabulary-driven difficulty, and the distinction matters for the edit. A vocabulary problem is fixed by swapping words. A sentence-architecture problem is fixed by restructuring, which is what this analysis is built to isolate.

One round trip to the server, then a structural breakdown.

Step 1

Paste the passage, up to 12,000 characters. A longer sample gives the model more of Claude's sentence architecture to weigh.

Step 2

Run the check. The text is sent once to our server, read for structure and difficulty, and nothing further is done with it after the result returns.

Step 3

Review the estimate and whether it's being driven by sentence length or vocabulary. The output describes the prose; it does not rank it against other writing.

A generic word-difficulty check would report Claude's vocabulary as unremarkable and stop there, missing the actual source of a high reading-level estimate. This analysis attributes the score explicitly, identifying the long, nested sentences responsible rather than leaving the cause ambiguous.

That attribution changes what gets edited. Simplifying vocabulary in an already-plain sentence accomplishes nothing. Restructuring a front-loaded qualifying clause into its own sentence is what actually reduces the estimate.

Without that attribution, a reviewer risks spending an editing pass on vocabulary that was never the actual cause of the score, while the sentence architecture responsible for it goes untouched.

Claude is tuned toward completeness and nuance, favouring a caveat stated ahead of the main claim over one appended afterward as a separate sentence. That ordering extends the distance a reader must hold in working memory before the sentence resolves.

A reading-level formula weighs sentence length alongside word difficulty, so a long sentence composed entirely of plain words can score higher than a shorter sentence using marginally harder vocabulary. This tool reports the two dimensions separately so the actual driver is never left ambiguous.

No. A grade level elevated by sentence length can reflect legitimate nuance rather than a defect. Claude's qualifying clauses frequently carry information a shorter sentence would have to omit.

Read the estimate against the intended audience. A technical or research readership may be well served by exactly this architecture. A general readership usually benefits from the qualifying clauses being split out.

One tool, several reasons to reach for it before a document ships.

Editorial reviewers

Checking whether Claude-drafted copy has drifted into unnecessarily nested sentences for a general readership.

Research teams

Confirming a Claude-assisted summary reads at the level intended for its actual audience, independent of correctness.

Technical writers

Isolating whether a difficult passage is a vocabulary problem or a sentence-architecture problem before rewriting it.

Educators and trainers

Matching Claude-assisted material to the reading level appropriate for its intended learners.