Pages Don't Have Doctype Declared
Pages Without Doctype Declaration
Is a technical issue sometimes flagged during a site audit in Semrush. The issue means that an HTML page is missing the document type declaration that tells browsers how to interpret the page.
Without this declaration, browsers may switch to an outdated rendering mode. That can cause layout inconsistencies, validation errors, and unpredictable behavior across devices.
Once you understand where the doctype belongs, the fix usually takes only a few minutes.
What is Pages Without Doctype Declaration?
Pages without a doctype declaration are HTML pages that do not include the <!DOCTYPE html> line at the very beginning of the document.
The doctype declaration tells browsers which version of HTML the page uses. Modern websites typically use HTML5, which is declared with a simple <!DOCTYPE html> line.
When the declaration is missing, browsers may enter "quirks mode." In quirks mode, the browser tries to render the page using outdated rules designed for older websites. That can create inconsistencies in how the page appears and behaves.
In most WordPress websites, this declaration is already included in the theme's header file.
Why does Pages Without Doctype Declaration affect SEO?
Pages without a doctype declaration can create rendering and validation problems that affect how browsers and search engine crawlers interpret a page.
Search engines like Google rely on clean and consistent HTML structure when crawling a site. When a page renders incorrectly because of quirks mode, elements such as navigation, layout containers, or structured content may not appear as expected.
This does not automatically cause ranking loss. However, rendering problems can lead to poor usability, layout issues on mobile devices, or difficulty interpreting page structure. Over time, those issues can affect how search engines understand and evaluate the page.
Maintaining a valid HTML document structure removes this risk.
