CSS absolute units and zoom disabled Accessibility Checkpoint


Use relative units in CSS property values when zoom is disabled by meta viewport.


Either allow the user to zoom content using pinch-zoom by removing user-scalable=no from the meta viewport tag (easiest), or allow the user to increase text size by using relative units like em and not absolute units like px and pt

Applicable standards

Note: Section 508 Refresh (2017) checkpoints are equivalent to WCAG 2.0 level A and level AA checkpoints.

Change history

  • 5.31 Nov 2018 Now only triggers when zoom disabled. Changed rule ID from AccWcag1-3.4.1 to AccHtmlNoTextResize.
  • 5.23 Oct 2016 Fixed false positive on fallbacks.
  • 5.22 Jul 2016 Fixed false positive on print media.
  • 5.3 Sep 2013 Fixed false positive.
  • 5.2 May 2013 Corrected WCAG 2 priority level (was A instead of AA).
  • 4.5 Nov 2011 Don’t complain about using absolute units when zero used (because 0px = 0pt = 0em = 0%).
  • 4.3 Apr 2011 Pick up CSS absolute units used in font: shorthand as well as font-size:.
  • 4.3 Apr 2011 Now triggers WCAG 2 1.4.4.
  • 3.5 Dec 2009 Modified rule to match intention of original author of guideline: http://lists.w3.org/Archives/Public/w3c-wai-gl/2004JanMar/0187.
  • 3.0 Dec 2008 Now triggers WCAG2 issue.
  • 1.0 Feb 2007 Added.

This page describes a web site issue detected in HTML documents by SortSite Desktop and OnDemand Suite.

Rule ID: AccHtmlNoTextResize