Readability Score Calculator

A readability score calculator analyses your text and produces a score that indicates how easy it is to read, based on sentence length, word length, and syllable count. It is used by content writers, educators, UX writers, and marketers who want to ensure their writing is accessible to their intended audience.

How to Use the Readability Score Calculator

1. Paste or type your text into the input field. Use at least a few sentences for a meaningful result.
2. Click the calculate button.
3. The tool displays one or more readability scores along with the approximate reading level.
4. Review which grade level or audience the score corresponds to.
5. Revise your text if needed, aiming for shorter sentences and simpler words to lower the score.

The Formula

Several readability formulas exist. The most widely used is the Flesch Reading Ease score:

Flesch Reading Ease = 206.835 - (1.015 x ASL) - (84.6 x ASW)

Where:

• ASL = Average Sentence Length (total words / total sentences)
• ASW = Average Syllables per Word (total syllables / total words)

Scores range from 0 to 100. Higher scores indicate easier text. A score of 60 to 70 is considered standard and accessible to adults with an average education. Scores above 80 are suitable for younger readers; scores below 30 are appropriate only for academic or technical audiences.

The Flesch-Kincaid Grade Level formula converts this into a US school grade equivalent:

FK Grade = (0.39 x ASL) + (11.8 x ASW) - 15.59

Other common formulas include the Gunning Fog Index, the SMOG Index, and the Coleman-Liau Index, each weighting sentence length and word complexity slightly differently.

Real-World Example

A health information website publishes an article for general patients. After pasting 400 words of draft text, the tool returns:

• Flesch Reading Ease: 52 (fairly difficult)
• Flesch-Kincaid Grade Level: 11 (US grade 11, age 16 to 17)

The intended audience is adults of all educational backgrounds, so a grade 6 to 8 target would be more appropriate. The writer shortens long sentences and replaces words like "contraindicated" with "not recommended". After revision, the score improves to 68, making the content accessible to a much wider audience.

Interpreting Readability Scores by Audience

Frequently Asked Questions

What Flesch score should I aim for in blog posts? For general audience blog posts, aim for a score of 60 to 70. If your audience is highly educated or specialist, scores in the 50 to 60 range are acceptable. For consumer-facing content aimed at the widest possible audience, target 70 or above.

Does a lower readability score mean the content is bad? Not necessarily. Academic journals, legal documents, and technical manuals are appropriately complex for their audiences, and a low score is expected. Readability scores are most useful when there is a mismatch between the complexity of your text and the needs of your readers.

What is the difference between Flesch Reading Ease and Flesch-Kincaid Grade Level? Flesch Reading Ease produces a score from 0 to 100 where higher is easier. Flesch-Kincaid Grade Level converts the same underlying factors into a US school grade, where a score of 8 means the text is appropriate for an eighth grader. Both formulas use average sentence length and syllables per word, but with different weighting and scaling.

How can I improve my readability score? The most effective changes are shortening sentences (aim for an average of 15 to 20 words), using shorter words where possible (preferring "use" over "utilise"), and breaking up long paragraphs. Avoid passive voice and nested clauses, which increase sentence complexity without adding clarity.

Scoring a passage by hand

The arithmetic is easier to trust once you have run it on a short passage. The text below is seven sentences and 75 words.

The tool counts the words and the sentences in your text. It divides the word count by the sentence count to get the average sentence length. Then it counts the syllables in every word and divides by the word count. Those two numbers feed the formula. A short sentence and a short word both raise the score. Long words lower it fast. Most writers gain more from cutting a clause than from swapping one word.

Those two figures feed every formula on this page.

Flesch Reading Ease = 206.835 minus (1.015 multiplied by 10.714286) minus (84.6 multiplied by 1.293333) = 206.835 minus 10.875000 minus 109.416000 = 86.5440.

Flesch-Kincaid Grade Level = (0.39 multiplied by 10.714286) plus (11.8 multiplied by 1.293333) minus 15.59 = 4.178571 plus 15.261333 minus 15.59 = 3.8499.

Six formulas on the same passage

The passage above scores very differently depending on which formula you apply. The table shows all six commonly used measures on the identical text.

The spread runs from grade 3.85 to grade 8.84 on one piece of writing. Anyone quoting a single readability figure should say which formula produced it, because the four grade measures are not interchangeable.

The arithmetic behind the last four:

Gunning Fog = 0.4 multiplied by (10.714286 plus 9.333333) = 8.0190, where 9.333333 is the share of words with three or more syllables, as a percentage of 75.

SMOG = 1.0430 multiplied by the square root of (7 multiplied by 30 divided by 7) plus 3.1291 = 1.0430 multiplied by 5.477226 plus 3.1291 = 8.8418.

Coleman-Liau = (0.0588 multiplied by 434.666667) minus (0.296 multiplied by 9.333333) minus 15.8 = 6.9957, where 434.666667 is letters per 100 words and 9.333333 is sentences per 100 words.

Automated Readability Index = (4.71 multiplied by 4.346667) plus (0.5 multiplied by 10.714286) minus 21.43 = 4.3999.

What moves the score

Sentence length and word length carry very different weights, and knowing which one to attack saves editing time.

Hold average syllables per word at 1.50 and vary the average sentence length:

One extra word per sentence costs 1.015 Flesch points. Adding thirteen words per sentence, which is a substantial rewrite of the rhythm, moves the score from 67.76 to 49.49.

Now hold the average sentence length at 17 and vary the syllables per word:

Each additional 0.10 syllables per word costs 8.46 Flesch points. That is more than eight times the cost of shortening a sentence by a word. Swapping utilisation for use, and commence for start, moves the number further than splitting a clause.

The two levers are not equally available. A technical subject forces some long words and no headline change removes them. Sentence length is the lever the writer controls completely.

A three step revision ladder

The tables above show what is possible. A worked revision shows what the steps are worth.

The first draft is 48 words in two sentences, with an average sentence length of 24 and 1.9583 syllables per word. It scores 16.8028 on Flesch Reading Ease.

Splitting sentences without changing a single word gained 12.18 Flesch points and took the grade level from 16.88 to 12.20. Replacing the long words and trimming thirteen words gained a further 57.78 points.

Note what the middle row does not do. It improves the score while the text still contains every difficult word from the draft. Readers notice the shorter sentences first, and the vocabulary second, which is why the sentence split is the step to take before the thesaurus.

Counting conventions and why they change the number

Two tools can score the same text five points apart without either being broken. The difference is in the counting rules.

Syllables are the usual culprit. This page uses the vowel group method: count each run of adjacent vowels as one syllable, then subtract one for a silent e at the end of a word unless the ending is le, ee or ye. Apply that rule and sentences is three syllables and formula is three.

Fire is the classic disagreement. Some counters return one syllable, others return two. A text with fifty instances of a word like that carries a difference of fifty syllables, which at 1.3 syllables per word is a meaningful movement in the score.

Numbers and abbreviations are handled differently too. Dates, currency amounts and acronyms may be counted as words, skipped entirely, or spelled out before counting. The passage above contains none of them, which is deliberate, because it makes the figures in the tables reproducible by hand.

Sentences need a rule as well. This page treats a full stop, a question mark and an exclamation mark as sentence ends, and it does not split on a decimal point inside a number or on a full stop inside an abbreviation.

What the figures above are not

The scores are mechanical. They say how hard the text is to decode, not whether it is any good. A short sentence can be vague and a long one can be exact.

They also apply poorly to lists, tables, code and dialogue, where sentence structure does not follow the pattern the formulas assume. A page made mostly of bullet points will score well and read badly.

The most useful comparison is between two versions of the same text, scored with the same tool on the same day.

Where the six formulas come from

The two Flesch formulas, and the statement that a Flesch-Kincaid level of 8 means a reader needs grade 8 reading to understand the text, come from the readability formula documentation published by Readable, fetched on 14 September 2026. The six formula values, the sensitivity tables and the revision ladder were all computed for this page from the word, sentence and syllable counts shown above.

The years and authors commonly attached to the Gunning Fog, SMOG, Coleman-Liau and Automated Readability Index formulas are not verified here. They are widely repeated and are given on the same site, but this page has not checked them against the original papers.

Also try these free tools:

• Reading Time Estimator
• Sentence Counter
• Word Counter