HTML page size checker
Check your HTML document size and get optimization recommendations
Check results
This check only covers HTML size. For a full picture of your page, run a page audit.
For issues across your whole site — duplicate titles, orphan pages, broken internal links — run a site audit.
Want us to fix what we found? Our team can help.
What is HTML size and why it matters
HTML size is the raw byte length of the HTML document the server sends — before CSS, JS, or images are fetched. It matters for two distinct reasons. First, Google has a documented hard cap: since February 2026, Googlebot stops fetching after the first 2 MB of an HTML response. Anything past that point is effectively invisible to Google — not indexed, internal links not followed, Schema.org markup ignored. Second, even well below the cap, oversized HTML slows page loading on mobile networks and increases memory pressure during parsing and rendering. The median page today is roughly 33 KB of HTML on mobile (Web Almanac 2025) — most pages don't need much more than that.
What this tool checks
- HTML byte size — graded against the 2 MB Googlebot cap and the ~33 KB mobile median
- DOM element count — flagged as excessive above 1500 elements per Lighthouse audit
Size thresholds
- Up to 100 KB — at or near the mobile median, no concern
- 100 KB - 500 KB — within normal range for content-heavy pages
- 500 KB - 2 MB — significantly larger than typical; worth auditing for inline JSON, unused markup, inline CSS/JS
- Over 2 MB — past Google's indexing cap. Content after the 2 MB mark is invisible to Google
Good vs bad examples
Good — lean HTML under 100 KB with markup for the real content:
<!DOCTYPE html>
<html>
<head>
<link rel="stylesheet" href="/styles.css">
<script src="/app.js" defer></script>
</head>
<body>
<main>... content ...</main>
</body>
</html>Bad — huge inline JSON / Redux state / template bundle in HTML:
<script>
window.__INITIAL_STATE__ = { /* 800 KB of server state */ };
</script>
<style>
/* 200 KB of inline CSS */
</style>Common mistakes
- Server-rendering huge JSON blobs — SPA frameworks embed Redux/Vuex state, tRPC caches, or Apollo snapshots in HTML. Kilobytes add up fast
- Inline everything — inline CSS and JS don't get cached, inflate every HTML response, and can't be loaded in parallel
- Template bloat — hidden modals, lazy-loaded sections, and all route variants pre-rendered in HTML instead of lazy-loaded
- Over-nested markup — dozens of wrapper divs per component add both bytes and DOM elements
- Long lists without pagination — 10,000-row product tables pushed into HTML rather than paginated or virtualized
- Ignoring the 2 MB cap — the top 2 MB are what Google sees. Everything below that is lost for SEO