Readability Score Calculator
Six readability formulas and a consensus grade for your text.
Enter some text to score it.
How readability scores work
Flesch Reading Ease rates text 0–100 (higher is easier); aim for 60+ for a general audience. The other five map onto a U.S. school grade instead. Flesch-Kincaid uses words per sentence and syllables per word; Gunning Fog uses sentence length and the share of complex words; SMOG counts polysyllables; Coleman-Liau and the Automated Readability Index use letters per word rather than syllables, so they disagree with the others on purpose. The consensus grade is their mean.
Two caveats the numbers alone hide. SMOG is defined on a 30-sentence sample — below that it is labelled unreliable rather than shown as a confident grade. And Gunning Fog's “complex words” are not SMOG's polysyllables: both start from words of three or more syllables, but Fog discounts a word that only gets there through an-es,-ed or-ingending, so “created” counts for SMOG but not for Fog. Both counts are shown above. Syllable counting is a heuristic, not a dictionary. Everything is computed in your browser.
More writing tools: the reading time calculator, the word counter, and the keyword density checker.
Built and maintained by Meet Shah · Last updated
What this tool is used for
- Checking whether a draft is pitched at the audience it is written for.
- Comparing two drafts on sentence and word complexity.
- Finding the paragraph that is dragging a document's score down.
- Checking documentation against a target reading level.
- Reviewing copy written for a general audience by a specialist.
Frequently Asked Questions
- Which formulas does it report?
- Flesch Reading Ease, Flesch-Kincaid Grade, Gunning Fog, SMOG, Coleman-Liau and the Automated Readability Index, plus the counts each one rests on — words, sentences, syllables, complex words and polysyllables.
- Why do the grades disagree with each other?
- Because they measure different things on purpose. Flesch-Kincaid and Fog use syllables; Coleman-Liau and ARI use characters per word instead. A text heavy in short technical terms scores very differently under the two families.
- Is SMOG reliable on short text?
- No. SMOG was calibrated on samples of thirty sentences, and below that it is an extrapolation rather than a measurement — which is why it is flagged as an estimate here rather than presented as a confident grade.
- Are Fog's complex words the same as SMOG's polysyllables?
- No, and the difference catches people out. Both start from words of three or more syllables, but Fog discounts a word that only reaches three through a common suffix such as -ed or -es. "Created" counts for SMOG and not for Fog.
- What is a good Reading Ease score?
- Roughly 60 to 70 is plain English suitable for general audiences; below 30 is heavy going. Most publishers target 60 or above for consumer material, and legal or academic writing routinely sits far below it.
- Do these scores mean my writing is good?
- No. They measure sentence length and word length, nothing more — they cannot see whether the argument holds, whether the vocabulary is apt, or whether the text is accurate. A low grade level and bad writing coexist easily.
Common errors and gotchas
- Treating the grade level as a quality measure, when a low score can mean choppy writing.
- Applying an English-tuned formula to another language, where the syllable assumptions do not hold.
- Scoring technical content whose necessary terms are long, and then removing precision to improve the number.
- Writing to the score rather than the reader, which produces short sentences that no longer connect.
- Assuming one score, when the formulas disagree and each measures something slightly different.