The Page Size Checker is a free online tool that measures the total file size of any webpage. Enter a URL and instantly see how heavy the page is — broken down by HTML, CSS, JavaScript, and image assets. Use it to diagnose slow load times, identify oversized resources, and prioritise performance improvements for better Core Web Vitals scores and SEO rankings.

What Is Page Size?

Page size is the total amount of data a browser needs to download to render a webpage. It includes the HTML document itself, all linked CSS stylesheets, JavaScript files, and images referenced in the page. A smaller page size means faster load times, which directly impacts user experience and search engine rankings.

Page weight is one of the most important factors in web performance. Google's Core Web Vitals measurements — especially Largest Contentful Paint (LCP) and Cumulative Layout Shift (CLS) — are heavily influenced by how quickly a page's assets can be downloaded and rendered.

Why Page Size Matters for SEO

Google has incorporated page speed as a ranking signal since 2010, and the introduction of Core Web Vitals in 2021 made performance metrics even more central to organic search rankings. A heavy page creates several problems:

• Higher bounce rates: Users on mobile connections or slower devices abandon pages that take more than 2–3 seconds to load.
• Reduced crawl efficiency: Googlebot has a crawl budget for each site. Large pages consume more of that budget, which can delay the indexing of newer content.
• Poor LCP scores: Large images and render-blocking JavaScript are the most common causes of a poor Largest Contentful Paint score.
• Lower ad revenue: If you run ads, slower page load times reduce viewability and click-through rates.

What Is a Good Page Size?

As a general guideline:

• Under 1 MB: Good. Most pages on fast connections will load within 2 seconds.
• 1 MB to 3 MB: Acceptable for desktop users, but may be slow on mobile. Worth optimising.
• Over 3 MB: Heavy. Likely to cause poor Core Web Vitals scores, especially on mobile and 4G connections.

The Google PageSpeed Insights threshold for a "good" page experience targets an LCP under 2.5 seconds, which is very difficult to achieve with pages over 3 MB on average connection speeds.

How to Reduce Page Size

1. Optimise Images

Images are typically the largest contributor to page weight. Use modern formats like WebP or AVIF instead of PNG or JPEG, compress images before upload, and implement responsive images with the srcset attribute so mobile devices load smaller versions.

2. Minify CSS and JavaScript

Removing whitespace, comments, and redundant code from CSS and JS files can reduce their size by 20–40%. Build tools like Vite, webpack, and Next.js handle this automatically in production mode.

3. Remove Unused Code

Tree-shaking during the JavaScript build process removes code that is imported but never called. Similarly, tools like PurgeCSS can remove CSS rules that do not match any HTML elements in the project.

4. Implement Lazy Loading

Defer the loading of images and iframes that appear below the fold with the loading="lazy" HTML attribute. This reduces the initial page payload to only what is needed to render the visible viewport.

5. Enable Browser Caching

Set long-lived Cache-Control headers on static assets so returning visitors load files from their browser cache rather than re-downloading them from the server.

How This Tool Works

This page size checker fetches the HTML of the target URL from our server, parses it to extract linked external assets (CSS, JavaScript, and images), and measures the size of each asset. Results are grouped by category so you can quickly identify which type of resource is contributing the most to your total page weight.

Note that dynamically loaded assets (fetched by JavaScript after the page loads) are not captured, and server-side compression (gzip, brotli) may mean the actual bytes transferred over the network are smaller than the uncompressed sizes shown here.