Check the real total page weight of any URL — powered by Google PageSpeed Insights. See total size broken down by images, JavaScript, CSS and fonts. Get Core Web Vitals, performance score, load time estimates and the top issues to fix — for both mobile and desktop.
Powered by Google PageSpeed Insights — measures total page weight (HTML + CSS + JS + images + fonts) for both mobile and desktop.
Paste the full URL of any publicly accessible webpage. The tool runs a real Google PageSpeed Insights analysis — the same data Google uses to rank your page — for both mobile and desktop simultaneously.
The headline number is total page weight: every byte downloaded to render the page, including images, JavaScript, CSS, fonts and the HTML document itself. A visual bar shows how each resource type contributes to the total.
LCP, CLS and TBT are the three Core Web Vitals Google uses as ranking signals. The tool shows your score for each with a clear pass/fail. The top opportunities section lists the highest-impact changes to reduce page size and improve speed.
How the total weight of your page directly determines load speed, bounce rate, and where you rank on Google
Webpage size is the total amount of data a browser has to download before your page is fully visible to a visitor. It is not just the HTML file. It is every image, every stylesheet, every JavaScript file, every font, and every third-party script that loads when someone lands on your page. Add all of those bytes together and you have your total page weight.
Page weight is one of the most direct contributors to slow load times. A browser cannot show your content any faster than it can download the files required to build it. The heavier your page, the longer that takes. On a typical mobile 4G connection, every additional megabyte of page weight adds roughly one full second to your load time. For most websites, that single number explains most of the gap between where they rank and where they want to rank.
The SEO connection is direct. Google uses page speed as a ranking factor. Since 2021, Core Web Vitals which are heavily influenced by page weight have been an official part of Google’s ranking algorithm for mobile search. A page that is too heavy will score poorly on Largest Contentful Paint, struggle with Total Blocking Time, and hurt your rankings regardless of how good the content on it is.
Most website owners have no clear picture of how heavy their pages actually are. A site gets built, images get uploaded without compression, plugins get installed, tracking scripts get added, and page weight quietly grows. Six months later that page is loading 4MB of data before a single word is readable. Checking your webpage size regularly is how you catch this before it becomes a serious ranking and revenue problem.
Total weight, resource breakdown, Core Web Vitals, performance score, load time estimates, and the top fixes — all from a single URL
Most webpage size tools show you one number in kilobytes. The Visiblytics Page Size Checker is powered by the Google PageSpeed Insights API — the same data source Google uses when evaluating your page for rankings. Here is everything you get from a single check.
The headline result is your total page weight in kilobytes or megabytes across every resource the browser downloads. Alongside the raw number you get a size grade from A to F mapped against Google’s recommended thresholds, so you immediately know whether you are within budget or significantly over it.
Below the total weight, a visual bar breaks down exactly where those bytes are coming from. You can see at a glance which resource type is doing the most damage to your page weight.
Core Web Vitals are the three metrics Google uses as direct ranking signals in mobile search. The tool shows LCP, CLS, and TBT with a clear pass, warn, or fail badge against Google’s exact published thresholds so you know immediately whether your page is at risk of a ranking penalty.
Your page weight means different things on different connections. The tool converts your total weight into estimated load times on slow 3G, 4G, and broadband. This gives you an honest picture of the experience visitors on slower mobile connections are actually having, which is the experience Google prioritises in its ranking decisions.
The opportunities section lists the highest-impact changes you can make to reduce your page weight, ranked by the number of bytes each fix would save. Every item shows the exact potential saving in KB or MB so you can prioritise the changes that will move your score the most before touching anything else.
The tool runs a full Google PageSpeed analysis for both mobile and desktop simultaneously. Results are presented in separate tabs. Always review the mobile tab first. Google uses mobile-first indexing, which means the mobile performance score is the one that determines your rankings. Desktop scores are typically 15 to 25 points higher than mobile for the same page because desktop tests simulate faster network conditions.
From a quick single-page check to a full 20-URL site audit with CSV export
The tool has two modes. Single URL mode for a quick deep-dive on one page, and bulk mode for auditing multiple pages at once and comparing them side by side. Both are completely free with no account required.
Paste any live, publicly accessible URL and click Analyse Page. The tool runs a real Google PageSpeed Insights analysis from Google’s own servers. This takes 15 to 30 seconds because it is a genuine live audit, not a cached or simulated result. You get full results for both mobile and desktop, including total weight, resource breakdown, all six performance metrics, Core Web Vitals status, and the full opportunities list.
Switch to bulk mode and paste up to 20 URLs, one per line. The tool analyses each URL and builds a comparison table showing total weight, mobile performance score, desktop performance score, size grade, and all three Core Web Vitals for every URL on the list. Download the full results as a CSV file to share with your development team, include in a client report, or track improvement over time.
The five issues the page size checker flags most often, and the practical steps to resolve each one
After running hundreds of page size checks, the same five issues appear in the opportunities section on most sites. Here is what they are and exactly what to do about each one.
Images are responsible for the majority of page weight on most websites. The fix has three parts. First, compress every image before uploading using a tool like Squoosh or ShortPixel. Second, convert images to WebP format, which delivers the same visual quality at 25 to 35 percent smaller file sizes compared to JPEG or PNG. Third, add lazy loading to images below the fold so they only download when the user scrolls to them. On WordPress, a plugin like Imagify or ShortPixel handles compression and WebP conversion automatically on upload.
Most websites load significantly more JavaScript than any individual page actually uses. Page builder plugins, ecommerce platforms, sliders, and third-party integrations all load their full JavaScript bundles on every page even when only a small fraction of those functions are needed on that specific page. The fix is code splitting combined with deferring non-critical scripts. On WordPress, WP Rocket and Perfmatters are the most effective tools for reducing unused JavaScript without breaking site functionality.
Enabling GZIP or Brotli compression on your server reduces the size of all text-based files including HTML, CSS, and JavaScript by 60 to 80 percent before they are transmitted to the browser. This is a server-level setting that your hosting provider or CDN can typically enable in minutes. It applies to every page on your site simultaneously and is one of the highest-impact, lowest-effort changes available to any website owner.
CSS and JavaScript files loaded in the document head prevent the browser from rendering any visible content until those files have fully downloaded and processed. Moving non-critical CSS to load after the initial render and deferring or async loading JavaScript that is not required for above-the-fold content can significantly reduce the time before your visitor sees anything on screen. Google PageSpeed Insights flags every render-blocking resource by name so you know exactly which files to target.
Every analytics tag, chat widget, social share button, ad script, and tracking pixel adds external network requests that your server cannot control or optimise. Audit your third-party scripts using the resource breakdown, remove anything that is not actively contributing value, and delay the loading of non-essential scripts until after the main page content has fully rendered for the user.
Why most free webpage size checkers only give you a number, and what you actually need to fix the problem
Knowing your page weighs 3.2MB tells you there is a problem. It tells you nothing about what is causing it, which metric it is affecting, how bad the user experience is on a real mobile connection, or what to fix first. That is the gap between a basic webpage size checker and the Visiblytics Page Size Checker. Here is the honest comparison.
| Feature | Visiblytics | Toolsaday | SEOptimer | SmallSEOTools |
|---|---|---|---|---|
| Total page weight | ✓ Yes | ✓ Yes | ✓ Yes | ✓ Yes |
| Resource breakdown by type | ✓ Images, JS, CSS, fonts | ✗ Not shown | ✓ HTML, CSS, JS, Images | ✗ Not shown |
| Core Web Vitals | ✓ LCP, CLS, TBT | ✗ Not shown | ✗ Not shown | ✗ Not shown |
| Google performance score | ✓ 0-100 score | ✗ Not shown | ✗ Not shown | ✗ Not shown |
| Load time by connection speed | ✓ 3G, 4G, broadband | ✗ Not shown | ✗ Not shown | ✗ Not shown |
| Mobile AND desktop results | ✓ Both simultaneously | ✗ Not shown | ✗ Not shown | ✗ Not shown |
| Top fix opportunities | ✓ Ranked by impact | ✗ Not shown | ✗ Not shown | ✗ Not shown |
| Bulk check (no login) | ✓ Up to 20 URLs free | ✗ Single URL only | ✗ Single URL only | ✓ Up to 10 URLs |
| CSV export | ✓ One click, free | ✗ Not available | ✗ Not available | ✗ Not available |
| Powered by Google PSI | ✓ Same data Google uses | ✗ Basic HTTP fetch | ✗ Basic HTTP fetch | ✗ Basic HTTP fetch |
Toolsaday, SEOptimer, and SmallSEOTools all work the same way underneath — they make a basic HTTP request to your URL and measure the size of what comes back. That gives you a total byte count. What it does not give you is any understanding of what is making your page heavy, whether that weight is hurting your Google rankings, what the experience is like on a real mobile connection, or what to fix first. The Visiblytics Page Size Checker is powered by the Google PageSpeed Insights API, which means the data comes from the same engine Google itself uses.
Auditing multiple pages at once? Switch to bulk mode, paste up to 20 URLs, and get a full comparison table with Core Web Vitals, performance scores, and size grades for every URL — with one-click CSV export, completely free, no account needed.
Total page weight is the sum of every resource downloaded when a user visits your page — HTML, CSS, JavaScript, images, fonts and third-party scripts. It directly determines how fast your page loads. Google recommends keeping total page weight under 1.6MB. Every extra megabyte costs roughly 1 second of load time on a 4G connection.
An HTML size checker only measures the initial document (typically 30–200 KB). This tool measures total page weight — everything the browser downloads to render the full page, which is typically 5–20x larger. Most users and Google care about total weight, not just HTML size.
Core Web Vitals are three metrics Google uses as direct SEO ranking signals. LCP (Largest Contentful Paint) measures how quickly the main content loads — good is under 2.5 seconds. CLS (Cumulative Layout Shift) measures visual stability — good is under 0.1. TBT (Total Blocking Time) measures main-thread blocking — good is under 200ms. Failing these hurts your rankings in mobile search.
Results are powered by the Google PageSpeed Insights API — the same engine behind Google's own PageSpeed Insights tool. Google runs a real Lighthouse audit on your page from their servers, so results reflect what Google actually sees, not a simulation. This is the most authoritative source for web performance data available.
The most common culprits are unoptimised images (not compressed, not in WebP/AVIF format, not lazy-loaded), unused JavaScript (large bundles where only a fraction is needed), render-blocking resources (CSS and JS loaded in the head before content), and excessive third-party scripts (analytics, ads, chat widgets, social embeds).
Google Lighthouse scores range from 0 to 100. 90–100 is Good (green), 50–89 is Needs Improvement (orange), and 0–49 is Poor (red). For SEO purposes, aim for 90+ on mobile. Desktop scores are typically 10–20 points higher than mobile because desktop has faster simulated network conditions. The mobile score is the one that affects Google rankings.
