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Find out more about the readability formulas and algorithms that power ReadablePro.
What is the Flesch-Kincaid Grade Level?
The Flesch Kincaid Grade Level is a widely used readability formula. It assesses the approximate reading grade level of a text. The Flesch-Kincaid Grade Level is equivalent to the US grade level of education. It shows the required education to be able to understand a text. The formula is as follows: Flesch Kincaid Grade Level formula For information, please read our article on [the Flesch Re
What readability algorithms do you use?
Readable is the most comprehensive readability tool. Readable currently uses: Grade Levels Flesch-Kincaid Gunning Fog Coleman Liau SMOG Automated Readability Index FORCAST Powers Sumner Kearl Rix Graphs Raygor Readability Graph Fry Readability Graph Scores Flesch Reading Ease CEFR IELTS Spache Dale-Chall Lix Lensear Write New scores are regularly added.
Why is your Linsear-Write formula different?
I understand you may be thinking, "Isn't it Linsear-Write? How come other readability tools like readabilityformulas.com and Hemingway Editor use Linsear-Write but yours is different?" If you're an avid user of Linsear-Write along with other formulas, we get why this might be alarming - that we're the only site who use it this way. The fact is, we're the only site that's using this particular readability formula the way it was intended. There are simply no reliable sources that point to Lin
What is the Gunning Fog Index?
The Gunning Fog index is a commonly cited readability scoring formula. The Gunning Fog formula generates a grade level, typically between 0 and 20. The formula estimates the years of formal education the reader requires to understand the text on first reading. So, if a piece of text has a grade level readability score of 6 then this should be easily readable by those educated to 6th grade in the US schooling system, i.e. 11-12 year olds. For more information, please read our blog:
What is the Flesch Reading Ease?
Flesch Reading Ease, developed by Rudolph Flesch in 1948, is a readability test. The score on the test will tell you roughly what level of education someone will need to be able to read a piece of text easily. The Flesch Reading Ease formula generates a score usually between 0 and 100 (although it is possible to generate scores below and above this banding). A higher s
What is the SMOG index?
SMOG is a readability framework which can be used to analyze how readable text is. It assesses how many years of education the average person needs to have to understand a piece. For more information on the SMOG framework, where it came from and why it's useful, see our blog on the topic here.
What is CEFR?
CEFR - The Common European Framework of Reference for Language - is an analysis of language skills. It can be applied to any language. It provides a methodology for language learning across Europe. It can also be used in a readablity context. This is so that you can reach a global audience. Aim for a CEFR B2 level. This is vantage or upper-intermediate. Visit our article for more information on CEFR.
What is the Automated Readability Index (ARI)?
The ARI assesses the U.S. grade level required to read a piece of text. We use the ARI formula along with several others in our bespoke algorithms to give you a unique overall readability rating. You can read more about ARI and its origin here.
What is the Coleman-Liau Index?
Developed in 1975 by Meri Coleman and T. L Liau, the Coleman-Liau Index is one of the most commonly used readability formulae. Classic readability tools involve counting the number of syllables per word and per sentence. Yet, the Coleman-Liau Index doesn't count any syllables. Coleman & Liau argued that techniques designed to estimate the number of syllables lacked accuracy. For more information, please read our blog: [Readability and the Coleman-Liau Index](https://readable.io/bl
What is Spache?
Spache is a readability test for English best for texts up to fourth-grade level. We keep it separate from our primary selection of algorithms we use to calculate our unique and reliable readability score. This is because it's a specialist tool meant for a specific age group. Spache calculates sentence length along with unfamiliar or difficult words according to a set list of familiar words for young children. If you have any questions about our range of algorithms, please don't hesitate to
What are ReadablePro’s letter grades? How are ratings calculated?
ReadablePro’s letter grades are our own unique readability score. We factor in all of the scores from the other readability algorithms we use and create an overall score. One that is quick and easy to understand. Ratings are from A to E. A rated text is very easy to read for the general public. E rated text is very hard to read. We are in the process of tweaking and improving these ratings, so we are not publishing the calculations we use for them at the moment. We do plan to publish o
How is IELTS calculated?
The IELTS score is mapped from the CEFR score and the following contribute to CEFR in our algorithm: Sentence complexity and well-known words Word list and list of names Average word and sentence lengths Lowering the score can be done by reducing your average sentence length, using more widely-used words and simplifying sentences.