About Readability

Readability is a measure of how easy your content is to read. It is a key factor in SEO and user experience. Find out more about readability and the formulas we use.

What is readability?

Readability is a measure of how easy a piece of text is to read. It can include elements of complexity, familiarity, legibility and typography. Readability formulas usually look at factors like sentence length, syllable density and word familiarity as part of their calculations.

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The benefits of readability

Readability has a host of benefits for your writing. It saves time and money as well as boosting profitability and increasing engagement. 

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The history of readability

The history of readability has its roots in education. Its development over the years is connected to technological and consumer rights change. 

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Readability formulas

Flesch Reading Ease and the Flesch Kincaid Grade Level

Rudolf Flesch created the most well-known and widely-used readability formulas. Flesch Reading Ease gives a score out of 100. Flesch Kincaid converts the readability score to a US education grade. Flesch scores can be applied to any type of content. 

About Flesch scores

SMOG Index

SMOG estimates the U.S. grade level required to understand the text. It is considered the gold standard formula in healthcare.

About the SMOG Index

Gunning Fog Index

Gunning Fog estimates the U.S. education level required to understand the text. It can be particularly useful for researchers writing papers.

About the Gunning Fog Index

Automated Readability Index

ARI assesses the U.S. grade level required to read a piece of text. It is best suited to technical writing.

About the Automated Readability Index

Spache Formula

Spache is a specialist formula designed for elementary age children. It can be used for texts up to fourth-grade level.

About Spache

New Dale Chall

New Dale Chall is a specialist formula designed for elementary age children. It can ensure a text is suitable for fourth-graders.

About New Dale Chall

Powers Sumner Kearl

Powers Sumner is a specialist formula designed for elementary age children. It is best fr children between second and fourth grade.

About Powers Sumner Kearl

Raygor Graph

Raygor is a graph-based readability formula. It calculates the US grade level of a text. It is best used for middle-school education.

About Raygor

Coleman Liau Index

Coleman-Liau is a readability formula which shows the reading level of a text. It is best used for professional documents. 

About the Coleman Liau Index

Fry Graph

Fry is a formula used to calculate the U.S. grade level required to understand a piece of text. Its use is wide-ranging but is particularly useful in education.

About Fry readability

IELTS

IELTS determines English language proficiency. Our IELTS test is useful for ensuring your writing is accessible for ESL readers.

About IELTS

CEFR

CEFR is designed to analyse language skills. It can be used to reflect on the global accessibility of your text.

About CEFR

Lix and Rix

The Lix formula gives a difficulty score. The Rix output is a U.S. grade level. Both can be used to test the readability of several non-English languages.

About Lix and Rix

The Lensear Write Readability Formula

Lensear Write determines writability as well as readability and it focuses on writing style. It's useful in government but can be applied to a variety of texts.

About Lensear Write

The FORCAST Readability Formula

The FORCAST formula determines a readability grade level. It was originally formulated for training material. It is most useful for technical writing.

About FORCAST

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