Eight formulas, one verdict
Readability formulas estimate how hard a text is from measurable features (sentence length, word length and syllables). Each was built for a different purpose, so they disagree, and the average is usually more stable than any one score. Textkiln shows them all:
| Formula | Measures | Best for |
|---|---|---|
| Flesch Reading Ease | words per sentence, syllables per word (0–100, higher is easier) | general text; widely used in plain-language laws |
| Flesch–Kincaid Grade | same inputs, expressed as a US school grade | education, US government documents |
| Gunning Fog | sentence length and “complex” words (3+ syllables) | business writing |
| SMOG | polysyllabic words; designed for 30 sentences | health information |
| Coleman–Liau | letters per word instead of syllables | quick automated scoring |
| ARI | characters per word and words per sentence | technical documents |
| Linsear Write | easy vs. hard words | technical manuals (US Air Force) |
| FORCAST | one-syllable words only | non-narrative text like forms |
| LIX | long words (7+ letters); language-independent | Scandinavian and European languages |
What score to aim for
For a general web audience, most guides suggest Flesch Reading Ease of 60 or higher and roughly grade 8. Patient information is often written at grade 6. Academic and legal writing runs higher, but even expert readers move faster through simpler prose.
Lowering the score
- Split long sentences: the Hardest sentences table shows where to start.
- Prefer short, common words: “use” for “utilize”, “help” for “facilitate”.
- Replace stacked nouns (“customer onboarding process improvement plan”) with a verb.
Formulas don’t understand meaning: a string of short nonsense words scores as “easy”. Use the score as a signal, then read the text yourself.
Worked example
Here is what the Readability Checker returns for its built-in example. Settings used: Target audience: Web & news (grade 8). Click Try an example in the tool above to load it, then change it as you like.
In order to succeed, the report was written by the team in a timely manner. It is important to note that the results were very, very good.
Basically, at the end of the day, we really need to think outside the box and leverage our synergy. Their is a lot of work to do, and the the deadline is close.
The chairman said that you guys should of known better. Its a fact that the data was analysed carefully and the color of the charts was chosen for clarity.| Result | Value |
|---|---|
| Reading ease | 77 |
| Grade level (average) | 7.1 |
| Words | 89 |
| Sentences | 6 |
| Words / sentence | 14.8 |
| Syllables / word | 1.36 |
Questions
What is a good Flesch Reading Ease score?
Around 60–70 is plain English that most adults read comfortably. Above 80 is very easy; below 30 is difficult, typical of academic papers and legal text.
What grade level should I write at?
For the general public, grade 7–8. For health information, grade 6. Specialist audiences tolerate higher, but simpler is almost always faster to read.
Why do the formulas give different grades?
They weight different features (syllables, letters, long words) and were calibrated on different texts. Use the average and look at the trend as you edit.
How are syllables counted?
With the open-source syllable library, which applies English pronunciation rules plus an exceptions list. It is right for most words but can differ on names and unusual words.
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