1.4.12 Text Spacing (AA)

Success Criterion 1.4.12 Text Spacing (Level AA):

In content implemented using markup languages that support the following text style properties, no loss of content or functionality occurs by setting all of the following and by changing no other style property:

Line height (line spacing) to at least 1.5 times the font size;
Spacing following paragraphs to at least 2 times the font size;
Letter spacing (tracking) to at least 0.12 times the font size;
Word spacing to at least 0.16 times the font size.

Exception: Human languages and scripts that do not make use of one or more of these text style properties in written text can conform using only the properties that exist for that combination of language and script.

Intent:

This success criterion allows users to use custom CSS to add additional spacing to the text that they see, without losing parts of the information on the page or overlapping text. It also allows users to change the font of the text on the page to one that is slightly wider than the original font. Keep in mind that these requirements build on the requirement that text be zoomable to 200% without loss of content or overlapping.

Exception:

“Human languages and scripts that do not make use of one or more of these text style properties in written text can conform using only the properties that exist for that combination of language and script.”

These spacing requirements are not applicable for all written languages. For example, letter spacing is not applicable for languages written using logographs instead of letters, such as Chinese. Word spacing and line height, however, would still be applicable in this case.

Who it helps:

Users with dyslexia who find it easier to read with extra spacing
Users with dyslexia who use custom fonts.

“Most text is hard to read. It's so cluttered I can't keep my focus. Just increasing the space between lines makes all the difference. When I'm really tired, I also increase the space between words.
- Student with dyslexia

Example:

Bad example: Text overflows container when respaced.

"Carry out a random act of kindness, with no expectation of reward, safe in the knowledge that one day someone might do the same for you."
- Princess Diana

In this example, the height of the div containing the text is set using pixels (px), so it does not expand with the content. Either setting div height in relation to font height using 'em,' or not setting div height at all, would prevent the text from overflowing the div.