Readability Formulas
Our scores are backed up by established readability algorithms and verified by over 10,000 automated tests and hand-calculated scores. You can be confident in your results.
- Flesch Kincaid Grade Level
- Flesch Kincaid is the most popular reading grade level across a wide range of sectors. You can rely on Readable to use the most up-to-date calculation methods to give you the most accurate Flesch Kincaid Grade Level.
- Gunning Fog Index
- Gunning Fog is a Grade Level based readability score. Originally created as a human algorithm, it's now included in our suite of digital readability solutions. Use Gunning Fog to help you keep your writing clear and simple.
- Coleman-Liau Index
- Originally intended for the standardisation of school books, Coleman-Liau is now widely used across sectors. It's also often used alongside other Grade Level formulas. Readable uses Coleman-Liau alongside a host of other highly respected and validated algorithms. Coleman-Liau helps you understand how to improve your writing.
- SMOG Index
- Considered the “gold standard” in medical writing, the SMOG Index is popular in the healthcare sector. Medical writers have found SMOG useful when working to make doctors' jargon more accessible to the public. SMOG Index will help you involve your patients in their healthcare decisions.
- Automated Readability Index
- The Automated Readability Index - ARI - was originally developed for typewriters. No need to tabulate your text or submit a sample - Readable scores your text as a whole within seconds. Quick ARI results which are easy to understand will help you edit technical documents and training literature for clarity.
- FORCAST Grade Level
- The FORCAST formula was originally developed for the US army for training new personnel. Because it's a powerful tool for evaluating incomplete sentences, it's now useful for a wide range of documents including questionnaires. Use the FORCAST formula to ensure forms, exam papers, surveys and more are suited to your reader.
- Powers Sumner Kearl Grade
- If you're an educator or a writer with an audience up to fourth grade, Powers Sumner Kearl is a great resource for you. It was developed for elementary school texts and generates a Grade Level that's easy to understand.
- Lix & Rix Readability
- Lix and Rix are both readability formulas validated by cloze tests. They've both been shown to work with both English and non-English texts. If you're evaluating readability in a language other than English, these formulas are a useful option. Rix outputs a Grade Level and is especially useful in the education sector.
- Raygor Readability
- The Raygor formula is a solution for middle school level texts to separate books into different levels of difficulty.
- Fry Readability
- Fry is a graph-based formula which can be used for elementary to college-level texts. It is highly regarded across a wide range of sectors. No need to interpret a graph - Readable does this for you within seconds behind the scenes.
- Flesch Reading Ease
- Flesch Reading Ease calculates a score between 1 and 100, with a higher score being more readable.
- CEFR Level
- CEFR is an analysis of language skills. It has been used by governments to ensure their content is reaching a wide audience.
- IELTS Level
- IELTS is a language proficiency test. Readable has repurposed it as an innovative tool to check your writing is accessible for a wider audience. Aim for an IELTS Grade 6 on Readable to ensure your writing is inclusive.
- Spache Score
- Spache takes into account words which would be unfamiliar in an elementary setting and is a great solution for educators.
- New Dale Chall Score
- Dale Chall is a word list readability formula which is best used in an elementary school setting.
- Lensear Write
- Lensear Write was originally an internal style manual. Now it's used as a formula to improve readability and writeability - it takes style into account as well as complexity. Using Lensear Write with Readable encourages you to use stronger verbs and avoid passive phrases. It generates a score out of 100 - the higher the score, the better your writing.