Core Web Vitals explained: how to actually fix LCP, INP and CLS

Core Web Vitals Explained: How to Fix LCP, INP, and CLS

Core Web Vitals are a set of metrics that measure the performance of your website, providing insights into how users experience it. Google uses these metrics to evaluate the user experience and ranks pages accordingly. The three main components of Core Web Vitals are:

**Largest Contentful Paint (LCP)**
**First Input Delay (FID)**
**Cumulative Layout Shift (CLS)**

Largest Contentful Paint (LCP)

Largest Contentful Paint (LCP) measures the loading performance of your website by evaluating how long it takes for the largest content element (image, text, or video) to load. This element is typically the primary content that users see when they land on your page.

How to Improve LCP:

**Optimize Images:** Compress images without losing quality. Tools like TinyPNG or ImageOptim can help you reduce file sizes.
**Leverage Browser Caching:** Set up cache-control headers to ensure browsers cache images and other resources effectively.
**Reduce Third-Party Scripts:** Minimize the number of third-party scripts and iframes that can delay the loading of your main content.
**Use Lazy Loading:** Implement lazy loading for images and iframes to load them only when they are in the viewport.

First Input Delay (FID)

First Input Delay (FID) measures the time it takes for a browser to respond to a user's interaction (like clicking a button) after the page has loaded. This metric is only measured in the lab and is not directly reported by Google for the field (actual user experience).

How to Improve FID:

**Optimize JavaScript Execution:** Minimize the execution time of JavaScript by optimizing loops, reducing the number of DOM manipulations, and using async and defer attributes for scripts.
**Reduce Layout Thrashing:** Avoid frequent reflows and repaints by batching DOM updates.
**Minimize Third-Party Scripts:** Optimize or reduce the number of third-party scripts that run on your page.
**Use Web Workers:** Offload CPU-intensive tasks to web workers to keep the main thread responsive.

Cumulative Layout Shift (CLS)

Cumulative Layout Shift (CLS) measures the visual stability of your page by tracking how much the layout of your page shifts unexpectedly when content (like images or ads) loads. A high CLS score can be frustrating for users as it disrupts their ability to interact with the page.

How to Improve CLS:

**Size Images Correctly:** Ensure images have the correct dimensions and are not loaded with incorrect sizes, causing layout shifts.
**Use Intrinsic Sizing:** Use the `width` and `height` attributes for images and iframes to prevent layout shifts.
**Contain Inline Text Sizes:** Use CSS to contain the size of inline text and prevent it from causing layout shifts.
**Load Fonts Synchronously:** Use the `font-display: swap` property to ensure fonts are loaded in a way that doesn’t cause layout shifts.

Tools to Help You Measure and Improve Core Web Vitals

To effectively measure and improve your website’s Core Web Vitals, you can use the following tools:

**Lighthouse:** A free, open-source tool from Google that audits your website and provides detailed reports on LCP, FID, and CLS.
**PageSpeed Insights:** Another Google tool that provides a summary of your website’s performance and suggestions for improvement.
**WebPageTest:** A tool that allows you to run tests from various locations and browsers, providing detailed reports on your website’s performance.
**GTmetrix:** Offers detailed performance reports and suggestions for improving your website’s speed and Core Web Vitals.

Conclusion

Improving your website’s Core Web Vitals is crucial for providing a better user experience and enhancing your search engine rankings. By optimizing images, reducing third-party scripts, and containing layout shifts, you can significantly improve your LCP, FID, and CLS. Using the right tools can help you measure and monitor these metrics effectively.

If you want a ready-to-use system to manage your Core Web Vitals, the SEO Audit Toolkit packages these improvements into a streamlined process.

Want this as a ready-to-run system? Get the SEO Audit Toolkit →

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