ZenovayTools

Page Size Analyzer

Analyzes a URL's page weight — fetches HTML and resource headers to break down estimated size by type (JS, CSS, images, fonts), detect HTTP/2 or HTTP/3, and grade transfer efficiency.

How to Use Page Size Analyzer

  1. 1Enter the URL you want to analyze.
  2. 2The tool fetches the page and checks resource sizes via HTTP headers.
  3. 3Review the breakdown by resource type and first-party vs third-party.
  4. 4Identify oversized resources and optimization opportunities.
Zenovay

Track your website performance

Real-time analytics, session replay, heatmaps, and AI insights. 2-minute setup, privacy-first.

Try Zenovay Analytics — Free

Related Tools

Meta Tag AnalyzerAnalyze meta tags of any webpage. Check title, description, Open Graph, Twitter cards, and get SEO recommendations.
Open Graph CheckerPreview how your page looks when shared on Facebook, Twitter, and LinkedIn. Check all OG and Twitter Card tags.
HTTP Header CheckerInspect HTTP response headers of any URL. Check security headers, caching, content type, and more.
Robots.txt ValidatorValidate and analyze your robots.txt file. Check rules, sitemaps, and common crawling issues.

Frequently Asked Questions

What does the page size analyzer measure?▾
It fetches the HTML of your URL and then sends HEAD requests to the first 25 resources found (scripts, stylesheets, images, fonts). For each, it records Content-Length (size), Content-Encoding (compression), Cache-Control, and whether it's a third-party resource. It then summarizes total page weight by resource type.
Why is page weight important for SEO?▾
Google uses Core Web Vitals as ranking factors. Page weight directly affects Largest Contentful Paint (LCP) and First Contentful Paint (FCP) — heavier pages load slower and score lower. Pages under 500KB typically score much better on Core Web Vitals than pages over 3MB. Every extra second of load time increases bounce rate by ~32%.
What is a "third-party resource"?▾
A third-party resource loads from a different hostname than the page itself. Examples: Google Fonts, CDN-hosted jQuery, Facebook Pixel JS, Google Analytics, embedded YouTube videos, social share buttons. Each third-party resource adds a separate DNS lookup (30-100ms) and is subject to that third party's privacy policy and data collection.
What is HTTP/2 and why does it matter for performance?▾
HTTP/2 allows multiple resources to be downloaded over a single connection simultaneously (multiplexing), reducing the cost of many small files. HTTP/1.1 only allows 6 parallel connections per hostname, causing queuing delays on resource-heavy pages. Most modern CDNs and hosting platforms support HTTP/2. HTTP/3 (QUIC) improves this further for high-latency connections.
Why do some resources show "unknown size"?▾
Resources served without a Content-Length header (common with chunked transfer encoding or dynamic content) cannot report their size without downloading the full file. This tool only sends HEAD requests to avoid downloading resources, so chunked resources show as unknown size. This is a known limitation of header-only analysis.
What is a good total page weight?▾
Google recommends keeping pages under 1.8MB for optimal Core Web Vitals. Under 500KB is excellent. 500KB-1.5MB is acceptable. 1.5MB-3MB needs attention. Over 3MB will likely cause poor Core Web Vitals scores, especially on mobile. The single biggest wins are usually image optimization (WebP format, lazy loading) and removing unused JavaScript.
How is this different from GTmetrix or Pingdom?▾
GTmetrix and Pingdom load the page in a full headless browser, executing JavaScript and rendering everything. This tool uses pure HTTP HEAD requests — no browser, no JavaScript execution. It's much faster (3-5 seconds vs 30-60 seconds) but cannot detect dynamically-loaded resources or resources injected by JavaScript after page load. Use this for quick checks; use GTmetrix for comprehensive audits.