15 · Text size, style, blinking elements and Readability

Web 2.0 Services

Items that flash or blink at a certain rate can cause seizures and should be avoided. They can also be very distracting and make other elements on a page hard to read. Complex small text and serif fonts can also make text harder to read for some people with cognitive learning disabilities and specific learning differences including dyslexia. The language used needs to be understandable for all users including those who have been deaf since birth or for whom English is not their first language. The language of the page can be programmatically determined.

Outcomes and Scores

This test has 4 possible outcomes.

Outcome Score
Sans-serif fonts used in all body content (excludes headings). Regular font size (12pt equivalent or larger) throughout and reasonable layout. 100%
Some serif text. Majority of text is larger than equivalent to 10pt. 67%
Variable between serif and sans-serif. Fonts smaller than equivalent to 10pt. Overly complex language used. 33%
Any blinking or flashing content that flashes more than three times in one second. Site unreadable. 0%


The results of this test are taken into account when calculating accessibility scores for the following disabilities.


The following technique may come in handy when running this test.


This test aims to cover the following sections of best practice.

Document Section Heading
WCAG 2.1 2.3 Seizures and Physical Reactions More Info
WCAG 2.1 3.1 Readable More Info