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    Critical CSS Generator: Generate Critical CSS

    Critical CSS generator that lets you generate critical CSS for any URL. Extract above-the-fold styles to inline for faster LCP.

    Critical CSS Generator: Generate Critical CSS illustration
    How it works: Paste a page's rendered HTML and its CSS. The tool keeps only rules whose selectors match elements in the HTML. For best results, paste only the above-the-fold HTML. True viewport-aware critical CSS requires headless rendering (Puppeteer, critters).

    How to use the Critical CSS Generator

    1. 1Paste your HTML and full CSS into the inputs.
    2. 2Click Generate to extract above-the-fold styles.
    3. 3Inline the critical output into your <head>.
    4. 4Defer the rest of your CSS for later.

    What you can do with the Critical CSS Generator

    Generate critical CSS for a landing page.

    Extract just the styles needed for first paint.

    Generate critical CSS for WordPress.

    Paste your rendered HTML and theme CSS to get an inline-ready snippet.

    Reduce render-blocking CSS.

    Inline critical styles, then defer the full stylesheet for faster LCP.

    Improve Core Web Vitals.

    Critical CSS is one of the highest-impact fixes for slow Largest Contentful Paint.

    Critical CSS Generator FAQs

    What is critical CSS?+

    The minimum CSS needed to render above-the-fold content. Inlining it lets the browser paint immediately without waiting for the full stylesheet.

    How big should critical CSS be?+

    Aim for under 14 KB so the first response packet contains the styles needed to render.

    Does inlining CSS hurt caching?+

    Critical CSS isn't cacheable across pages, but the win on first paint usually outweighs the cost. Keep the rest of your stylesheet cacheable.

    Is my code uploaded?+

    No. Generation runs entirely in your browser.

    Will this work for dynamic apps?+

    Best for mostly-static pages. SPAs typically generate critical CSS at build time per route.

    Want your whole site this fast? Our team offers full website speed optimization — done for you .