Page size checker
How heavy is your page? See its total download size and request count, split by HTML, JavaScript, CSS, images and fonts, with the largest files listed so you know what to shrink first.
We download the page and every script, stylesheet, image and preloaded font it references, from a server in US East. Takes 5–20 seconds.
How heavy is too heavy?
Every byte costs time on a slow connection. Lighthouse’s mobile test simulates about 1.6 Mbps, which works out to roughly 200 KB per second, so a 3 MB page needs about 15 seconds just to download. Real 4G is usually faster, but plenty of visits happen on congested or rural networks.
| Resource | Comfortable budget (mobile) | Why it matters |
|---|---|---|
| Total page | ≤ 1.5 MB | Download time on slow networks, and data cost for visitors on metered plans |
| JavaScript | ≤ 300 KB compressed | Must also be parsed and run; hurts TBT and INP |
| CSS | ≤ 100 KB | Render-blocking: nothing paints until it arrives |
| Hero image | ≤ 150 KB | Usually the LCP element |
| Fonts | ≤ 100 KB, 2–3 files | Delay text rendering and can shift layout |
These are practical starting budgets, not official limits. Tighten them for pages that must load fast on mobile, such as landing pages and checkout.
How to reduce page size
- Images first. Resize to the size shown on screen, use
srcsetfor different screens, and convert to WebP or AVIF. - Cut JavaScript. Remove unused plugins, apps and tags, and split bundles so each page loads only its own code.
- Subset fonts. Load only the weights you use, as WOFF2, with the Latin subset if that’s all you need.
- Compress text. Turn on Brotli or gzip for HTML, CSS, JS and SVG.
- Replace autoplay video with a poster image and load the video on click.
Questions people ask
What is a good web page size?
There is no official limit, but lighter is faster. The HTTP Archive’s Web Almanac reports a median mobile home page of roughly 2 MB. Keeping a page under about 1.5 MB, with JavaScript under 300 KB compressed, gives slow phones a fair chance.
How do I check the size of a web page?
Enter the URL above. We download the HTML and each file it references and add up their transfer sizes. In your own browser, open Chrome DevTools → Network, reload, and read the “transferred” total at the bottom.
Why is the size here different from DevTools?
DevTools counts everything the page loads, including files requested later by JavaScript, lazy-loaded images and ads. We count files referenced directly in the HTML, from a server without cookies, so third-party and on-scroll content may be missing.
What makes a page heavy?
Usually images served larger than they are displayed, JavaScript bundles from frameworks, plugins and tag managers, web fonts with many weights, and autoplaying video.
Does page size affect SEO?
Indirectly. Google doesn’t rank by bytes, but heavy pages load slower and hurt Largest Contentful Paint, which is part of Core Web Vitals. Googlebot also stops reading an HTML file after its first 15 MB.