Does it work for languages other than English?

The formulas are calibrated for English, so scores for text in other languages are approximate and may be inaccurate.

Can I load a file instead of pasting text?

Yes, a .txt or .md file. Long-sentence highlighting is shown for texts up to 50,000 characters; the scores are still calculated for longer texts.

Yes. Every tool is free to use, with no account and no credit card. The work runs on your device rather than on our servers, which is what keeps it free to run.

Does it work on mobile?

Yes. It runs in current mobile browsers on iOS and Android, with nothing to install.

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Free Readability Score Checker

Q: Which readability scores does it show?

Six: Flesch Reading Ease, Flesch-Kincaid Grade, Gunning Fog, SMOG, Coleman-Liau and Automated Readability Index, plus word, sentence and syllable counts.

Score your writing with Flesch Reading Ease, Flesch-Kincaid Grade, Gunning Fog, SMOG, Coleman-Liau, and ARI. See the reading level instantly.

Runs in your browserNo sign-up, no pop-upsNo login requiredFree forever

Works offline once loaded

Your text

Common uses

Readability for Content MarketingMake sure your blog posts and landing pages are easy enough for your audience.
Readability for SEOImprove dwell time and engagement signals by writing at the right reading level.
Check Academic Writing LevelGauge whether your paper or thesis matches its intended reading level.
Plain-Language ComplianceGovernment and healthcare content often requires a specific reading level — verify it.
Readability for Email CampaignsKeep marketing and outreach emails skimmable and easy to read.

How It Works

This tool runs six classic readability formulas — Flesch Reading Ease, Flesch-Kincaid Grade, Gunning Fog, SMOG, Coleman-Liau, and Automated Readability Index — using hand-written JavaScript that executes entirely in your browser. No text is sent to a server at any point.

1
Tokenizing words and sentences
The tool splits your text on whitespace to count words, then uses a regex that matches runs ending in . ! or ? to count sentences. A minimum of one sentence is enforced so the formulas never divide by zero.
2
Counting syllables and complex words
Each word is passed through a heuristic syllable counter that strips silent-e endings, removes a leading y, then counts vowel clusters (aeiouy). Words with three or more syllables are flagged as 'complex words', the input required by Gunning Fog and SMOG.
3
Applying the six formulas
All six scores are derived from three primitives — words per sentence, syllables per word, and characters per word — using their published coefficients. For example, Flesch Reading Ease is 206.835 minus 1.015*(words/sentences) minus 84.6*(syllables/words). Coleman-Liau substitutes character counts for syllables, making it the only formula that does not depend on the syllable counter.
4
Sentence-level highlighting and target check
After scoring, the tool walks sentences a second time to flag those over 20 words (amber) or over 30 words (red), similar to the Hemingway Editor. If you set a target audience (marketing, general, or academic), each grade-level score is compared against a fixed grade threshold and shown with a pass or fail indicator.