Readability Score Calculator
Paste any writing and get its Flesch Reading Ease score and Flesch-Kincaid grade level instantly.
Runs entirely in your browser. Your text is never uploaded or stored.
How to use this tool
Paste or type your writing into the box above, then press Analyze text. The calculator counts the words, sentences, and syllables in your copy and uses those counts to compute two well known scores: the Flesch Reading Ease score and the Flesch-Kincaid grade level. You will also see the raw counts so you can spot long sentences or heavy multi-syllable words that drag the reading level up. Use the Load sample button if you want to see how a paragraph scores before pasting your own text.
How the Flesch Kincaid readability calculator works
Both formulas use the same three building blocks: total words, total sentences, and total syllables. Sentences are detected by end punctuation (period, question mark, exclamation mark). Words are the space-separated tokens. Syllables are estimated by counting vowel groups in each word, which is a common approximation used in text composition scoring tools.
Flesch-Kincaid Grade = 0.39 × (words / sentences) + 11.8 × (syllables / words) - 15.59
The Reading Ease score runs from about 0 to 100. Higher is easier: a score of 90 to 100 reads like a short, simple sentence, while a score under 30 reads like dense academic or legal text. The grade level maps the same data onto a US school grade, so a result of 8.0 means an average eighth grader should be able to follow the writing. Most general web copy aims for a Reading Ease of 60 or higher and a grade level around 7 to 8.
A real example
Take the sentence "The cat sat on the warm mat and looked at the bright sun." That is one sentence, 13 words, and about 14 syllables. Words per sentence is 13 and syllables per word is roughly 1.08. Plugging into the Reading Ease formula: 206.835 - 1.015 × 13 - 84.6 × 1.08, which gives about 102, capped near 100. That tells you the line is very easy to read. The grade level works out close to 0.5, meaning even an early reader could handle it. Swap in long technical words and watch both numbers move toward harder reading.
Common questions
What is a good readability grade level for web copy?
For most US websites and marketing copy, aim for a Flesch-Kincaid grade level of about 7 to 8, which matches a Reading Ease score near 60 to 70. That keeps your writing clear for a wide audience without sounding childish.
How accurate is the syllable count?
This tool approximates syllables by counting vowel groups in each word, the same shortcut most readability scorers use. It is very close for everyday English but can miss a few unusual words, so treat the result as a reliable estimate rather than a perfect count.
What is the difference between Reading Ease and grade level?
They use the same word, sentence, and syllable data but report it differently. Reading Ease gives a 0 to 100 score where higher means easier. The grade level translates that into a US school grade so you know roughly how much education a reader needs.
Why did my long sentences lower the score?
Both formulas penalize a high words-per-sentence ratio. Long sentences raise that ratio, which lowers the Reading Ease score and raises the grade level. Breaking long sentences into shorter ones is the fastest way to make copy easier to read.
Can I use these scores for school or professional work?
The scores are a helpful guide for analyzing your writing copy, but they only measure structure, not meaning, tone, or correctness. Use them as one input alongside your own editing judgement, not as a final grade.