# HTML size (SEO)

> HTML size is the weight of a page's HTML document in kilobytes, without images, styles and scripts. Search engines and browsers have to download and parse all of it.

- **Check ID:** S24
- **Area:** [SEO](https://be1st.ai/glossary/seo)
- **Tool:** [SEO + Security + Performance](https://be1st.ai/tools/ssp-audit)
- **Page:** https://be1st.ai/glossary/seo/html-size

## Why it matters

Large HTML documents slow down page loading, consume more memory, and can cause issues on mobile devices with limited data plans. Google favors fast pages.

## In practice

Single Page Applications (SPAs) sometimes generate HTML with inline CSS/JS exceeding 500 KB. 100 KB is a practical limit set by be1st for fast loading, not an official Google limit. WordPress themes with page builders often generate unnecessarily large HTML with dozens of superfluous div elements.

## How be1st checks it

Checks the size of the HTML document, which should not exceed 100 KB (up to 200 KB is a warning). Overly large HTML slows down parsing, rendering, and increases page load time.

[SEO + Security + Performance](https://be1st.ai/tools/ssp-audit), SEO tab.

Every check ends as: Pass, Warning, Fail.

## Sources

- [Lighthouse SEO Audits](https://web.dev/articles/pass-lighthouse-seo-audit) (web.dev)
- [SEO Starter Guide](https://developers.google.com/search/docs/fundamentals/seo-starter-guide) (Google Search Central)

## Related terms

- [HTML size (performance)](https://be1st.ai/glossary/performance/html-size): HTML size is the weight of a page's HTML document in kilobytes. The browser has to download and parse all of it before it can show the page.
- [Inline CSS](https://be1st.ai/glossary/performance/inline-css): Inline CSS is styling written directly in the HTML, in `<style>` blocks or style attributes, instead of in a separate stylesheet file.
- [Mobile-friendly indicators](https://be1st.ai/glossary/seo/mobile-friendly-indicators): Mobile-friendly indicators are the signs that a page adapts to small screens: a viewport tag, responsive CSS and content that fits without zooming.
- [Content length](https://be1st.ai/glossary/seo/content-length): Content length is the number of words of visible text on a page. A page with too little text rarely answers a question well enough to rank.
- [Keyword density](https://be1st.ai/glossary/seo/keyword-density): Keyword density describes how often the words a page targets appear in its text. Here it means whether the words from the title also show up in the content.
- [Hreflang tags](https://be1st.ai/glossary/seo/hreflang-tags): Hreflang tags tell search engines which language or regional version of a page to show to which users on a multilingual website.