Readability Score Calculator

Analyze text readability with Flesch-Kincaid, Gunning Fog, SMOG, Coleman-Liau, and grade level scores.

Readability Score Calculator tool

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Example

Input: Text: "The cat sat on the mat. It was a sunny day, and the children played happily in the garden near the old house."

Result: Flesch Reading Ease 92.2 (Very Easy), Flesch-Kincaid Grade 3.3, Gunning Fog 6.3, SMOG 7.2

23 words, 2 sentences, 28 syllables: FRE = 206.835 - 1.015 x 11.5 - 84.6 x 1.217 = 92.2; FK = 0.39 x 11.5 + 11.8 x 1.217 - 15.59 = 3.3.

Flesch Reading Ease Score Bands

ScoreLabel shownRough school level
90 and aboveVery Easy5th grade
80 to 89Easy6th grade
70 to 79Fairly Easy7th grade
60 to 69Standard8th to 9th grade
50 to 59Fairly Difficult10th to 12th grade
30 to 49DifficultCollege
Below 30Very DifficultGraduate
  1. Paste or type your text into the input area for analysis.
  2. Review the readability scores from all six formulas displayed side by side - Flesch Reading Ease, Flesch-Kincaid, Gunning Fog, SMOG, Coleman-Liau, and Automated Readability.
  3. Check the estimated US grade level, averaged across the grade-level formulas, required to understand your text.
  4. Examine the detailed statistics including sentence count, average words per sentence, and number of complex words.
  5. Revise your text to lower the grade level by shortening sentences and replacing complex words, then re-analyze.

Readability Scores and What They Mean

A readability score estimates how easy a text is to read from the length of its sentences and words. On the Flesch Reading Ease scale, higher is easier. A score of 60 to 70 is plain English that most adults read easily, and below 30 is dense, academic text.

This tool runs six formulas at once. Flesch Reading Ease gives a score, most often from 0 to 100. The other five give a US school grade: Flesch-Kincaid, Gunning Fog, SMOG, Coleman-Liau and the Automated Readability Index (ARI). Each weighs things a bit differently. Gunning Fog and SMOG count complex words of three or more syllables. Coleman-Liau and ARI count letters instead of syllables. The estimated grade level at the top is the average of the five grade formulas.

Paste your text to see the scores and the numbers behind them. You get word, sentence and syllable counts, average sentence length, syllables per word, complex words and average word length. Those numbers tell you what to fix. If sentences average over 20 words, split them. If there are many complex words, look for shorter ones, such as "use" for "utilize".

Syllables are counted by a set of rules, not a dictionary, so scores can differ a little from other tools. Very short texts, lists and code give odd results, so test at least a few paragraphs. A readability score measures surface features, not meaning. A text can score well and still be unclear. To check length as well, use the Word Counter.

Formula / How It Works

Flesch-Kincaid GL = 0.39 x (words/sentences) + 11.8 x (syllables/words) - 15.59. Flesch RE = 206.835 - 1.015 x (words/sentences) - 84.6 x (syllables/words). Gunning Fog = 0.4 x ((words/sentences) + 100 x (complex words/words)). SMOG = 1.043 x sqrt(complex words x 30 / sentences) + 3.1291. Coleman-Liau = 0.0588 x L - 0.296 x S - 15.8 (L = letters per 100 words, S = sentences per 100 words). ARI = 4.71 x (characters/words) + 0.5 x (words/sentences) - 21.43.

Frequently Asked Questions

For general web content, 60 or higher is a common goal, which matches about an 8th to 9th grade level. Scores of 70 to 80 read easily for most people. Legal and science writing often scores below 30. Aim for the level of your readers, not the highest number possible.
For a general audience, grade 7 to 9 is a common target, because it is easy for most adults without feeling childish. Technical guides for experts can go higher. The grade level here is an average of five formulas, so a single outlier formula has less effect.
Shorten long sentences, since sentence length has a big effect on every formula. Swap long words for short ones where the meaning stays the same. Cut filler phrases. Use lists for steps. Then paste the text again and compare the average sentence length and complex word count.
Each one uses different inputs. Flesch-Kincaid uses syllables per word, Gunning Fog and SMOG count words of three or more syllables, and Coleman-Liau and ARI count letters. Text with many short but uncommon words, or long but simple words, can split them apart. That is why the tool shows their average.

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