free tool
Online text checker: readability, keyword stuffing, filler
Paste your text and get a readability grade, keyword stuffing scores, filler share, top words, filler phrases and grammar notes in a couple of seconds. Up to 20,000 characters per check, free, no sign-up.
norms
How to read the scores
The thresholds match the ones we use for our own blog posts. For texts under 100 words, treat the numbers as rough.
| Metric | Target | What it shows |
|---|---|---|
| Flesch-Kincaid grade | 9 or lower | The US school grade needed to follow the text; shorter sentences and words lower it |
| Flesch reading ease | 60 or higher | A 0–100 scale: 60–70 is plain English, below 30 reads like a legal contract |
| Keyword stuffing (classic) | reference | Square root of how often the most frequent word appears; in English that is usually "the", so check the stop-word-free figure too |
| Keyword stuffing (academic) | reference | Share of the five most frequent meaningful words among all words, % |
| Filler share | reference | Share of stop words: articles, prepositions, pronouns, auxiliaries |
| Keyword density | reference | Share of the ten most frequent meaningful words among meaningful words, % |
| Filler phrases | 0 | Clichés such as "in this article" or "it is worth noting" |
| Grammar | 0 issues | Typos, repeated words, punctuation — checked by LanguageTool |
faq
Frequently asked questions
For web content, aim for grade 9 or lower: most readers skim, and short sentences survive skimming. Technical documentation can sit at 10–12; anything above 12 usually means sentences that need splitting.
It measures repetition. The classic score is the square root of how often the most frequent word appears: 49 uses give a score of 7. The academic score is the share of the five most frequent meaningful words. High values point to an overused keyword or a thin vocabulary.
No. The text goes to the App-Kit analysis service only for the duration of the check and is not kept after the response. Your IP address is not passed to the analysis service.
Up to 20,000 characters per check and up to 20 checks per hour from one address. Check long texts section by section.
Not in the free version: the tool measures text quality. Plagiarism checks need queries to an external search engine and are not part of this check.