Online Text Checker: Readability, Keyword Stuffing, Filler and Grammar

What a text checker measures

A text checker is a tool that turns a draft into numbers: how often words repeat, how long sentences run, how much of the text is function words, and how many typos slipped through. Each number comes with a target, so you know which paragraph to rewrite first.

Numbers do not replace an editor. They catch what your eyes stop seeing on the third read: one word on every line, forty-word sentences, stock phrases. Search engines judge whether a page helps people, not formulas, yet stuffed and heavy copy hurts both crawlers and readers.

How to check a text online in 4 steps

• Open the analyzer and paste your text — up to 20,000 characters per run, so check long posts section by section
• Press Check text or Ctrl + Enter: results arrive in 1–2 seconds
• Read the colors: green is on target, amber is borderline, red needs an edit
• Rewrite the paragraphs that hold the top words and flagged clichés, then run the check again

Readability: Flesch-Kincaid grade and reading ease

The Flesch-Kincaid grade estimates the US school grade a reader needs: 0.39 × words per sentence + 11.8 × syllables per word − 15.59. For web copy we aim for 9 or lower. Reading ease runs on a 0–100 scale where higher is easier; 60–70 is plain English, and below 30 reads like a contract.

Keyword stuffing: classic and academic scores

The classic score is the square root of how many times the most frequent word appears; a word used 49 times scores 7. In English that word is almost always "the" — this post scores 7.8 on it — so read the second figure, which skips stop words: 4.1 here. Words are counted by lemma, so "host" and "hosts" add up.

The academic score is the share of the five most frequent meaningful words among all words. It depends on length: our 191-word test paragraph hit 15.2%, while this whole post scores 5.9%. We treat it as a reference and read it next to the top-words list.

• A stop-word-free score above 7: one meaningful word repeats too often — swap some uses for pronouns or synonyms
• High academic score with a normal classic one: the text circles a few topics without detail
• Verbs like "provide" or "ensure" at the top of the list point to corporate tone, not stuffing

Filler share and keyword density

Filler share is the percentage of stop words: articles, prepositions, pronouns and auxiliary verbs. English needs a lot of them — this post comes in at 57% — so we keep the metric as a reference rather than a hard limit. Our padded test paragraph scored 70.2%.

Keyword density shows what share of meaningful words the ten most frequent ones take. A high value means the text orbits a narrow set of keywords. Short texts always score high here, so for anything under 100 words the analyzer marks frequency scores as rough.

One paragraph, measured before and after

We wrote a typical paragraph about choosing a web host — padded intro, repeated nouns, stock phrases — and rewrote it using the analyzer report: cut the opening, replaced vague words with numbers, split long sentences. Both versions went through the same engine as the public tool.

The grade dropped by more than 10 points, mostly because the average sentence shrank from 32 words to 11. The clichés went first: five of them carried no information, so deleting them changed nothing for the reader.

Clichés and grammar

The analyzer matches the text against a list of stock openers and transitions that tell the reader nothing. Matching ignores case and apostrophe style. Each hit is shown in the report, and you can usually delete it whole without touching the meaning of the sentence.

Grammar is checked by LanguageTool: typos, doubled words, punctuation. We keep it as a reference. In the edited paragraph above it flagged "uncached" and "PageSpeed" as spelling mistakes — product names and jargon trigger false positives, so read each note before you accept it.

Text checker or human editor

The pair works best. The checker clears mechanical problems in seconds, then the editor spends time on meaning, facts and voice. New posts on this blog pass that gate before they go live.

FAQ

What is a good Flesch-Kincaid grade for a blog post?

Grade 9 or lower. Most readers skim, and short sentences survive skimming. Technical documentation can sit at 10–12, but anything above 12 usually hides sentences that should be split in two.

How much text can I check for free?

Up to 20,000 characters per check and up to 20 checks per hour from one address, no sign-up. Checking a long post section by section also shows which part drags the scores down.

Does it check plagiarism?

Not in the free tool. A plagiarism check needs dozens of queries to an external search engine for every run. The public version measures quality: readability, stuffing, filler, clichés and grammar.

Why does a short text get bad scores?

Frequency scores are shares, and in 50 words every repeat weighs a lot. Keyword density and the academic score run high on any short paragraph. For texts under 100 words, rely on readability, clichés and grammar.

Is my text stored?

No. The text goes to the analysis service only for the duration of the check and is not kept after the response. Your IP address is not passed to the service.

Next: audit the whole page

Copy is one part of a page. Headings, meta tags, load speed and indexing are covered by the SEO audit, and the 18-point checklist walks you through the technical basics by hand.