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Adjustable Letter Spacing

Do you prefer reading text with the letters spaced more closely together or further apart? CISL users can adjust the amount of spacing between letters, allowing readers to explore which setting feels like the best fit for them. Readers with dyslexia in particular may want to use this feature, as some studies have found that they tend to benefit from increased letter spacing.

See what letter spacing options you prefer in Clusive.

Two images of the same article within the CISL reader environment are shown side-by-side. The article in the image on the right has letters that are more spaced out from one another, compared to the article in the left image. Above the two images a line of text reads “More or less space between letters?” with two arrows, one pointing to each image.

Some readers enjoy being able to increase the amount of space between letters. 


Increased letter spacing may improve reading outcomes among children, adolescents, and adults with dyslexia: 

  • A study of 74 children with dyslexia, ages 8 to 14, found that extra-large letter and line spacing improves text reading speed and accuracy.
  • A study of 61 sixth-grade children, 29 of whom had dyslexia, found that students with dyslexia needed larger letter spacing to identify letters than do students without dyslexia.
  • A study of 22 individuals with dyslexia, ages 13 to 37, found that the narrower the spacing between characters, the longer participants took to read a passage. Participants’ preferences were split between standard character spacing and more separated characters.

Related Guidelines 

The features of the CISL tools are related to existing guidelines and best practices, including the Web Content Accessibility Guidelines (WCAG) and the Universal Design for Learning (UDL) Guidelines. The feature of adjustable line spacing is connected to:

Web Content Accessibility Guidelines(WCAG)

  • To meet WCAG level AA, you need to design your content to still be usable if the user configures their system to increase letter spacing up to certain limits (WCAG 2.1 AA Criterion 1.4.12)

Universal Design for Learning (UDL) 

Adjustable Line Spacing in other work

Want to see what other projects are doing with Adjustable Line Spacing? See what Raising the Floor has compiled on their adjust text font, including size and spacing page.

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