Text readability checker
The tool measures the average sentence length, the average number of syllables per word, the share of long words and the share of very long sentences, folds them into a score from 0 to 100 using the Flesch formula, and shows the five hardest sentences in your text. It is worth knowing the limit straight away: this measures form, not quality. The formula sees exactly two things — sentence length and word length. An empty text can score high, and a strong expert analysis can score low. So the value here is not the score but the list of sentences worth rewriting.
Enter some text and the explanation of the maths appears here.
Five hardest sentences
| Sentence | Words | Long words |
|---|---|---|
| Enter some text and the hardest sentences appear here. | ||
This measures form, not quality. The formula sees only sentence length and the number of syllables in words. An empty text can score high, and a strong expert analysis can score low. No score here is a verdict: it does not say the text is good, and it does not say it is bad.
Sentence boundaries and syllable counts are approximate. For Ukrainian and Russian, syllables are counted by vowels; for English, by vowel groups, and both methods sometimes get loanwords, acronyms and proper names wrong.
Your text never leaves your browser: it is not sent to a server and is not stored anywhere.
How the score is calculated
The basis is Rudolf Flesch's readability formula: from the constant 206.835 it subtracts the average sentence length in words with one coefficient, and the average number of syllables per word with another. The result is clamped to the range 0 to 100. The coefficients depend on the language. For English, Flesch's original values are used: 1.015 and 84.6. For Russian it is Oborneva's adaptation, 1.3 and 60.1, because Russian words are longer than English ones and with the original coefficients any normal text would come out "very difficult". For Ukrainian the same coefficients as Russian are used: by average word and sentence length the two languages are close, and no separately calibrated formula for Ukrainian is publicly available. This is a deliberate approximation, and it is stated here plainly instead of being hidden in small print. Syllables are counted by vowels: in Slavic languages there are as many syllables as vowels. For English, vowel groups are counted with an adjustment for the silent final "e".
What the bands on the scale mean
80–100 — very easy, roughly a 5th to 6th grade level: short sentences, everyday words. News and children's books are written this way. 60–79 — easy, roughly a 7th to 8th grade level. This is the target band for a blog, a newsletter and most commercial writing. 40–59 — standard, roughly a 9th to 11th grade level. A business article, a review, a longread. It reads without strain but asks for attention. 20–39 — difficult: a university or trade-publication level. Appropriate if you write for colleagues, risky if you write for a wide audience. 0–19 — very difficult: the level of an academic paper or a contract. People read text like this when they have to. No band is a verdict. A contract belongs in the bottom band; a children's story in the top one is equally in the right place.
What to do with the hardest sentences
The table shows the five sentences with the greatest weight: length in words plus triple weight for words of four syllables or more. A long sentence made of short words reads more easily than a short one full of jargon, and the weight formula accounts for that. There are two common causes of hardness. The first is a sentence with two or three thoughts glued together by commas and a "since": it splits in half almost always without loss. The second is a chain of nouns built from verbs — "implementation of the optimization of operations" instead of "so it works better". A practical guide: if a sentence runs over 25 words, read it aloud. The place where you run out of breath is the place to break it. And do not chase the score. Chopping every sentence down to five words gives you 90 points and an unreadable staccato: the rhythm of a text lives in the alternation of long and short.
What this score does not do
It does not judge quality, meaning, logic, facts or correctness. A text with an error in every word gets exactly the same score as a proofread one, as long as the sentence and word lengths match. It takes no account of jargon or of how familiar the words are to the reader: "synchrotron" and "pastoral" look identical to the formula, though not to the reader. It does not distinguish genres. The same 35 points are normal for a legal text and catastrophic for a newsletter, and the formula knows nothing of that difference. Sentence boundaries and syllable counts are approximate: abbreviations, initials, acronyms and loanwords throw the count off from time to time. So read the score as a guide accurate to the band, not as an exact number.