How to Improve Core Web Vitals: A Step-by-Step Guide

Core Web Vitals are a set of metrics that Google uses to measure user experience on the web. They include Largest Contentful Paint (LCP), Interaction to Next Paint (INP), and Cumulative Layout Shift (CLS). Improving these metrics can boost your search rankings and keep visitors engaged. This guide walks you through practical steps to optimize each metric.

What Are Core Web Vitals?

• LCP (Largest Contentful Paint): Measures loading performance. Should occur within 2.5 seconds of when the page first starts loading.
• INP (Interaction to Next Paint): Measures responsiveness to user interactions across the whole visit. Should be 200 milliseconds or less. INP replaced First Input Delay (FID) as a Core Web Vital in 2024.
• CLS (Cumulative Layout Shift): Measures visual stability. Should be less than 0.1.

These metrics are part of Google's page experience signals, which influence rankings. Improving them not only helps with SEO but also creates a better experience for your users.

Step 1: Measure Your Current Performance

Before making changes, you need to know where you stand. Use free tools like:

• Google PageSpeed Insights – Provides lab and field data for both mobile and desktop.
• Chrome User Experience Report – Real-user data aggregated by Google.
• MyWebsiteScore – Run a free audit to get a comprehensive report on your site's performance, including Core Web Vitals.

Focus on the field data (from real users) as it reflects actual experiences. Lab data is useful for debugging but may not always match real-world conditions.

Step 2: Optimize LCP (Largest Contentful Paint)

The LCP element is typically an image, video, or large text block. Here's how to speed it up:

• Identify the LCP element – Use tools like Chrome DevTools to find what's causing the delay.
• Optimize images – Compress images, use modern formats like WebP, and implement lazy loading for below-the-fold images. For the LCP image, consider preloading it with a <link rel="preload"> tag.
• Reduce server response time – Use a content delivery network (CDN), upgrade your hosting, or implement caching (e.g., browser caching, server-side caching).
• Minimize render-blocking resources – Defer non-critical CSS and JavaScript. Inline critical CSS for above-the-fold content.
• Use a fast DNS provider – Ensure your DNS resolution is quick.

Step 3: Improve INP (Interaction to Next Paint)

INP measures how quickly your page responds to user interactions — clicks, taps, and key presses — throughout the visit. It replaced the older First Input Delay (FID) metric, which only measured the first interaction. To improve it:

• Break up long tasks – Large JavaScript tasks can block the main thread. Use techniques like code splitting, lazy loading, and web workers.
• Optimize JavaScript execution – Remove unused code, minify files, and use async or defer for non-critical scripts.
• Use a web worker – Offload heavy computations to a background thread so the main thread stays responsive to input.
• Preload key resources – Use <link rel="preload"> for fonts, scripts, or stylesheets that are needed early.

Step 4: Reduce CLS (Cumulative Layout Shift)

CLS occurs when page elements shift unexpectedly. Common causes include images without dimensions, ads, and embedded content. To fix:

• Set explicit width and height on all images, videos, and iframes. This reserves space before the resource loads.
• Reserve space for ads – Use static containers with defined sizes. Avoid late-loading ads that push content down.
• Avoid inserting dynamic content above existing content – For example, if a banner loads after the page, it should not push down the main content. Use a placeholder.
• Use font-display: swap for web fonts – This ensures text remains visible while the font loads, preventing layout shifts.
• Optimize animations – Use CSS transforms and opacity changes instead of properties that trigger layout (like width, height, top).

Step 5: Monitor and Maintain

Core Web Vitals are not a one-time fix. Continuously monitor your site:

• Set up Google Search Console reports for Core Web Vitals.
• Use Real User Monitoring (RUM) tools to track performance over time.
• Regularly audit your site with tools like MyWebsiteScore to catch regressions.

Common Mistakes to Avoid

• Ignoring mobile – Mobile performance often differs from desktop. Always test on actual mobile devices.
• Over-optimizing – Don't sacrifice functionality for speed. Test changes thoroughly.
• Forgetting third-party scripts – Analytics, ads, and social widgets can hurt performance. Audit their impact and consider alternatives.

Conclusion

Improving Core Web Vitals is an ongoing process that directly impacts user experience and SEO. Start by measuring your current performance, then tackle LCP, INP, and CLS with the steps above. Regularly monitor your site and make adjustments as needed. For more, browse our website performance guides.

For a comprehensive audit of your site's Core Web Vitals and other performance metrics, run a free website audit at MyWebsiteScore. It will give you prioritized fixes to improve your site's speed and user experience.

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