Readability Scorer
Score text with Flesch, Gunning fog, SMOG and Coleman-Liau, and find the hard sentences.
What These Formulas Can And Cannot Tell You
Every readability formula in common use counts two things: how long the sentences are and how many syllables the words have. That is all. They were built in the mid-twentieth century to grade school textbooks, and they measure a real correlate of difficulty — but they measure it very bluntly.
A page of short, simple, meaningless sentences scores beautifully. A precise technical explanation scores badly and may be perfectly clear to its readers. Treat a poor score as a prompt to reread a passage, not as a defect to be fixed by deleting commas.
Key features
- Six established formulas — Flesch reading ease, Flesch-Kincaid, Gunning fog, SMOG, Coleman-Liau and ARI.
- Names the hardest sentences — which is far more actionable than any single index.
- Handles abbreviations — "Dr." and "e.g." do not end a sentence, which throws off naive counters badly.
- Flags its own limits — SMOG needs thirty sentences to mean anything, and says so below that.
- Explains the number — with the reading level it corresponds to, rather than just a score.
This tool runs entirely inside your browser using native Web APIs. Your files and text are never uploaded to a server, never logged and never shared with third parties.
How to use: Readability Scorer
- Paste your text
A hundred words or more; below that the formulas are noisy. - Read the reading ease first
60 to 70 is the plain-English band that most public writing aims for. - Look at the hardest sentences
Usually three or four sentences are carrying the whole score. - Rewrite and re-check
Splitting the longest sentences moves every index at once.
Technical specifications
| Processing location | Entirely in your browser — no server round trip |
|---|---|
| Data uploaded | None. Files and text never leave your device |
| Price | Free — no account, no trial, no usage cap |
| Category | Text |
| Works offline | Yes, once the page has loaded |
| Browser support | Chrome 90+, Edge 90+, Firefox 90+, Safari 15+ |
| Interface languages | English, 中文, हिन्दी, Español, العربية |
Frequently asked questions
Which score should I pay attention to?
Flesch reading ease, because it is the one with a widely understood scale: 60 to 70 is plain English, below 30 is heavy going. The grade-level formulas mostly agree with each other, so tracking one is enough. Use the others when a house style or a regulator asks for a specific one.
What score should I aim for?
It depends entirely on the audience. Public health information and government guidance typically target reading ease above 60. A trade publication for specialists can sit far lower without being unclear, because its readers know the vocabulary. Writing down to an audience is its own failure.
Why does the syllable count look wrong on some words?
Syllable counting in English cannot be done reliably by rule — the same letters are pronounced differently in different words, and there is no way to know from spelling alone. The method here is the standard approximation the published formulas were calibrated against, so the scores match other tools even where an individual word is off by one.
Can I improve a score without improving the writing?
Easily, and it is worth knowing how so you can recognise it. Splitting every sentence at the conjunctions and swapping precise long words for vague short ones will move any of these numbers. It will not make the text clearer. The formulas measure a proxy, not the thing itself.
Why is SMOG flagged on my text?
The SMOG formula was defined over a sample of thirty sentences and is unreliable below that — its author was explicit about it. It is still shown for shorter passages because it is informative alongside the others, but with a note rather than a false air of precision.