Critical CSS Generator

Generate Critical CSS for Faster Page Loads

Extract the minimal CSS needed to render above-the-fold content. Improve page speed, Core Web Vitals, and search rankings with properly optimized Critical CSS.

Faster Page Loading

Improved Core Web Vitals

Better SEO Rankings

Critical CSS Generator

Generated CSS

critical.css

0 bytes

How to Use Your Critical CSS

Step 1: Inline Critical CSS

Paste the generated CSS inside a <style> tag within the <head> of your HTML document. Place it high up, before any other stylesheets or blocking scripts.

Remember you might need to change references to images or other assets

HTML Head Snippet

<style>
  /* Critical CSS for your website */
  /* The generated CSS will be added here when you copy this snippet */
</style>

Step 2: Load Non-Critical CSS (Simple)

Place your original non-critical CSS <link> tags just before the closing </body> tag. This allows the browser to render the initial content styled by the critical CSS first. Remember to remove these same links from your <head>!

HTML Body Snippet

<html>
    ...
    <body>
    ... 
      <link rel="stylesheet" href="/css/vendors.min.css">  // Example
      <link rel="stylesheet" href="/css/style.min.css">    // Example
    </body> 
  </html>

Step 3 (Optional): Defer with JavaScript

Alternatively, for potentially more optimized loading (especially on slow connections), use JavaScript in the <head> to load non-critical styles after the page content loads. Use this instead of Step 2. Update the `stylesheets` array and ensure the original links are removed from <head>.

JavaScript Head Snippet

window.addEventListener("DOMContentLoaded", function () {
  console.log("✅ Page loaded, now loading non-critical stylesheets...");
  // --- Define your non-critical stylesheets here ---
  let stylesheets = [
    // "/css/vendors.min.css", // Example
    // "/css/style.min.css",   // Example
    // Add all stylesheets that are NOT critical css
  ];
  // ----------------------------------------------
  let loadedCount = 0;
  function checkAllStylesLoaded() { 
    loadedCount++; 
    if (loadedCount === stylesheets.length) { 
      console.log("✅ All non-critical stylesheets loaded..."); 
    } 
  }
  
  stylesheets.forEach(function(href) { 
    var link = document.createElement("link"); 
    link.rel = "stylesheet"; 
    link.href = href; 
    link.onload = checkAllStylesLoaded; 
    link.onerror = () => console.warn(`Failed to load stylesheet: ${href}`); 
    document.head.appendChild(link); 
  });
});

How Our Critical CSS Generator Works

1. Load Page

Our tool loads your URL in a headless browser with the viewport dimensions you specify, allowing JavaScript to execute if needed.

2. Extract Elements & Styles

We identify all visible elements in the viewport, analyze their styles, and extract the relevant CSS rules from all stylesheets.

3. Optimize & Output

Finally, we compile and minify the CSS, keeping only what's needed for above-the-fold content, then provide implementation instructions.

Benefits of Using Critical CSS

Faster Perceived Load Times

Visitors see your page content much faster, as critical CSS is inlined and renders immediately without waiting for external stylesheets.

Better Core Web Vitals

Improve First Contentful Paint (FCP) and Largest Contentful Paint (LCP) metrics, which are key factors in search engine rankings.

Reduced Render-Blocking Resources

Eliminate render-blocking CSS by loading only what's needed first, then asynchronously loading the remainder.

Improved Mobile Experience

Mobile users on slower connections will see usable content much faster, reducing bounce rates and improving engagement.

Higher SEO Rankings

Google's page experience update rewards faster-loading pages with better search rankings, directly improving your visibility.

Decreased Page Weight

Initial page weight is significantly reduced by deferring non-critical CSS, speeding up the initial download and parse time.

Frequently Asked Questions

What is Critical CSS?

Critical CSS refers to the minimal set of CSS rules required to render the visible portion of a webpage (above the fold). By extracting and inlining this CSS into your HTML, the browser can render content faster without waiting to load all stylesheets, improving performance and Core Web Vitals.

How does the Critical CSS Generator work?

Our tool uses a headless browser to load your page, analyze which elements are visible in the specified viewport, extract their styles from all CSS resources, and compile a minimal set of CSS rules needed to display the above-the-fold content. You can customize viewport dimensions, rendering wait time, and JavaScript handling.

Why should I use Critical CSS?

Critical CSS significantly improves page load performance by eliminating render-blocking CSS and allowing the browser to display content faster. Benefits include faster perceived load times, better Core Web Vitals scores (especially FCP and LCP), improved SEO rankings, and better user experience, particularly on mobile or slow connections.

How do I implement Critical CSS on my website?

To implement Critical CSS, add the generated CSS inside a <style> tag in the <head> of your HTML documents. Then, load your regular stylesheets either at the end of the body (simple approach) or with JavaScript that loads them after the page content is rendered (advanced approach). Our tool provides code snippets for both methods.

Welcome
to SEOJuice

Generate Critical CSS for Faster Page Loads

Generating Critical CSS

Initializing Browser

Loading Page

Analyzing Viewport Elements

Extracting Critical CSS

Optimizing Output

Generated CSS

How to Use Your Critical CSS

Step 1: Inline Critical CSS

Step 2: Load Non-Critical CSS (Simple)

Step 3 (Optional): Defer with JavaScript

How Our Critical CSS Generator Works

1. Load Page

2. Extract Elements & Styles

3. Optimize & Output

Benefits of Using Critical CSS

Faster Perceived Load Times

Better Core Web Vitals

Reduced Render-Blocking Resources

Improved Mobile Experience

Higher SEO Rankings

Decreased Page Weight

Frequently Asked Questions

What is Critical CSS?

How does the Critical CSS Generator work?

Why should I use Critical CSS?

How do I implement Critical CSS on my website?

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Generate Critical CSS for Faster Page Loads