Page size (also called page weight) is the total amount of data a visitor's browser needs to download to display your page. It's measured in kilobytes (KB) or megabytes (MB). The bigger the page, the longer it takes to load — especially on mobile connections.
The average web page in 2025 is about 2.5 MB. That might not sound like much, but on a 3G mobile connection, that's 7-10 seconds of loading. On a fast connection, it might be 1-2 seconds. The difference in page size between a well-optimized site and a bloated one is often the difference between a customer who stays and one who leaves.
What makes pages heavy
Images (usually 50-80% of page weight)
Images are almost always the biggest contributor to page size. A single uncompressed hero image from a modern camera can be 5-8 MB — bigger than most entire web pages should be. Even "small" images from stock photo sites are often 1-2 MB each.
The fix is simple: resize images to the actual dimensions they'll be displayed at (not the original camera resolution), and use modern formats like WebP instead of JPEG or PNG. This alone can cut your page size by 60-80%. Your overall speed will improve dramatically.
Video
Background videos and auto-playing clips can add 5-20 MB per page. If you must use video, host it on YouTube or Vimeo and embed it rather than self-hosting. This means the video file doesn't load until someone actually clicks play.
JavaScript
Scripts add up fast. Your analytics, chat widget, social media buttons, A/B testing tools, and marketing pixels each add 50-200 KB. A typical small business site might have 15-20 scripts totaling 1-2 MB. The problem isn't just the download — JavaScript also has to be processed by the browser, which slows things down further.
Fonts
Custom fonts typically add 100-400 KB. Using more than two font families (or loading every weight and style) can push this higher. Google Fonts and system fonts are the lightest options.
CSS
Stylesheets are usually the smallest contributor, but frameworks like Bootstrap can add 200+ KB of CSS you're not actually using. If you're only using 10% of a framework, you're making visitors download 90% of unused code.
What's a healthy page size?
- Under 1 MB: Excellent — your page loads fast on almost any connection
- 1-2 MB: Good — reasonable for most pages with images
- 2-3 MB: Average — room for improvement, especially on mobile
- 3-5 MB: Heavy — noticeably slow on mobile connections
- 5+ MB: Too heavy — you're losing visitors, guaranteed
Your homepage should ideally be under 2 MB. Interior pages with less imagery can often be under 1 MB. Product pages with multiple photos should aim for 2-3 MB maximum, using lazy loading so images below the fold only download when the visitor scrolls to them.
How to measure your page size
The easiest way is to run a speed test — tools like GTmetrix and WebPageTest show total page weight and a breakdown by file type. You can also check in Chrome DevTools: open your page, press F12, click the "Network" tab, and reload. The total transfer size appears at the bottom.
Pay attention to the breakdown by type. If images make up 80% of your page weight (they usually do), that's where to focus your effort. If JavaScript is the dominant category, audit your scripts and remove what you don't need.
Quick wins for reducing page size
- Compress images. Use Squoosh, TinyPNG, or your CMS's built-in optimizer. Convert to WebP format.
- Remove unused scripts. Audit every third-party script. If you stopped using a service, remove its script tag.
- Lazy load images. Add
loading="lazy"to images below the fold. - Enable compression. Make sure your server sends files with gzip or brotli compression (most modern hosts do this by default).
Check your page size. Antileak measures your page weight, identifies the heaviest resources, and tells you exactly what to optimize. It's part of your website health score.