Readability is a basic design goal for anything meant to be read by a general population. Text meant for a general readership should have a reading grade level of at most 8. Better still would be a reading grade level of 6 or 7.
Online Readability Tools
For Webpages or Uploadable Documents
These FREE online readability tools allow your to test the readability of a particular webpage or document using a set of standard readability formulas. They don't require your to type or paste in the text to be analyzed.
- Juicy Studio
- Top of the heap for free online readability tools.
- Readability.Info
- Second banana, but still good.
Cut-and-Paste Tools
Online Readability Analysis of Text
This free online tools require you to type or cut-and-paste the text for analysis.
- Lexicool Textalyser
- From the website: "This text analysis tool provides information on the readability and complexity of a text, as well as statistics on word frequency and character count. It can be of assistance to translators when calculating quotes for clients."
- Okapi
- From the website: "The Internet Application
for Creating Curriculum-Based Assessment Reading Probes" -- geared towards teachers. - I Love Jack Daniels
- From the website: "This tool will give you three scores, telling you how easy text is to read. Simply enter the text you wish to check into the box below, and your scores will be calculated. More information about the Flesch-Kincaid readability scoring systems and the functions behind this tool can be found in the Flesch-Kincaid Reading Level article or the Gunning-Fog Index article."
Studies on Readability
When You Want Data
For a deeper understanding of readability, check out these reports.
- More reports on Usability Studies
- More recent reports from the original usability guy, Jakob Nielsen. See especially the section on teens.
- UseIt Reports on Usability Studies
- These reports are specifically about website usability, and come from the original usability guy, Jakob Nielsen.
- A First Look at the Literacy of America's Adults in the 21st Century
- Published by the National Center for Education Statistics, part of the U.S. Department of Education. From the report description: "The 2003 National Assessment of Adult Literacy (NAAL) measures the English literacy of America's adults (people age 16 and older living in households and prisons). NAAL builds on the previous national assessment of literacy completed in 1992. The 2003 assessment defines literacy as "using printed and written information to function in society, to achieve one's goals, and to develop one's knowledge and potential."
Readability at Amazon
Writing readable text
For those who want to write text to meet a readability goal.
Plain Language and the Document Revolution
Amazon Price: (as of 12/11/2009) 
The Penguin Guide to Plain English (Penguin Reference Books)
Amazon Price: (as of 12/11/2009)
The Quick Reference Plain English Guide
Amazon Price: (as of 12/11/2009)
The Dictionary of Concise Writing: 10,000 Alternatives to Wordy Phrases
Amazon Price: (as of 12/11/2009)
Write Tight: How to Keep Your Prose Sharp, Focused and Concise
Amazon Price: (as of 12/11/2009)
Readability at Amazon
Technical titles
For those who want to dig into the science behind the various readability tests.
Manual for Use of the New Dale-Chall Readability Formula
Amazon Price: $14.95 (as of 12/11/2009)
Usually ships in 24 hours
The Art of Readable Writing: With the Flesch Readability Formula
Amazon Price: (as of 12/11/2009)
Readability: Its Past, Present, and Future
Amazon Price: (as of 12/11/2009)
Readability Revisited: The New Dale-Chall Readability Formula
Amazon Price: $29.95 (as of 12/11/2009)
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by cehwiedel
I am a freelance writer (with a sideline in stock photography). One of my primary areas of interest is website design. Readability is important in web... (more)
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