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Page Size Checker

Measure HTML size, load time and the weight of scripts, styles and images.

What is page size?

Page size (page weight) is the total amount of data a browser downloads to show a page — the HTML plus scripts, stylesheets, images, fonts and other files. Heavier pages load slower, especially on mobile networks, which hurts Core Web Vitals and conversions.

What we measure

  • HTML size and load time of the document itself.
  • Up to 30 resources referenced in the HTML — scripts, stylesheets and images — sized from their Content-Length headers.
  • Totals per type so you can see whether JavaScript, CSS or images dominate.

Files loaded later by JavaScript, lazy-loaded images and fonts referenced only in CSS are not included, so real page weight in the browser is usually higher. Use Chrome DevTools (Network tab) or PageSpeed Insights for the full picture.

How heavy is too heavy?

The median mobile page today is around 2 MB. Aim lower: under 1 MB is fast on most connections, and the HTML document itself ideally under 100 KB compressed. JavaScript is the most "expensive" byte because it must be parsed and executed, not just downloaded.

How to reduce page weight

  1. Images: serve WebP or AVIF, resize to the displayed size, add loading="lazy" below the fold, and set width and height to avoid layout shift.
  2. JavaScript: remove unused plugins and third-party tags, defer non-critical scripts, and split large bundles.
  3. CSS: remove unused rules and inline only critical CSS.
  4. Compression: enable Brotli or gzip — check with the HTTP Headers Checker (look for content-encoding).
  5. Caching: long Cache-Control lifetimes for versioned assets.

Run a full on-page review with the SEO Audit, which also scores response time and HTML size.

Frequently asked questions

How do I check the size of a web page?

Enter the URL. You get the HTML size, load time and the sizes of up to 30 scripts, stylesheets and images, with totals per type.

What is a good page size?

Under about 1 MB loads quickly on most mobile connections. The HTML document itself should ideally stay under 100 KB compressed.

Why do some files show unknown size?

Some servers do not send a Content-Length header, especially for compressed or streamed responses.

Does page size affect SEO?

Indirectly. Heavy pages load slower and score worse on Core Web Vitals, which affects user experience and can affect rankings.

What usually makes pages heavy?

Unoptimised images and too much JavaScript from plugins, trackers and ad scripts.