DOM size

Why it matters

Every element costs memory, style calculation and layout time. Pages with thousands of elements respond slowly to taps and clicks (Interaction to Next Paint) and render slowly on phones.

How to fix it

1. Remove hidden duplicate markup, such as separate mobile and desktop menus.
2. Paginate or lazy-render long lists, comments and product grids.
3. Flatten deeply nested wrapper elements produced by page builders.

Check it with

• Page Speed Test – Lighthouse performance score, lab metrics and real-user Core Web Vitals for any page.
• Core Web Vitals Checker – Check real-user LCP, INP and CLS from the Chrome UX Report for a page and its whole site.

Scoring: a passed check earns its full weight, a warning half and an error none. How the SEO score works

Test your page All checks