Core Web Vitals: 10 Quick Wins to Improve LCP, CLS & INP
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Introduction
Core Web Vitals: What They Are & Why They Matter
H2. What Are Core Web Vitals?
Core Web Vitals are a set of metrics defined by Google to quantify user experience on the web, focusing on loading performance, interactivity, and visual stability.
The three key metrics currently are:
- Largest Contentful Paint (LCP): Measures how quickly the largest content element (image or text) becomes visible. A good threshold is 2.5 seconds or less.
- Cumulative Layout Shift (CLS): Measures how much unexpected layout shifts occur while a page loads — elements moving around unexpectedly. Lower is better: aim for 0.1 or less.
- Interaction to Next Paint (INP): The newer responsiveness metric, replacing FID. INP measures how quickly the page responds to user interactions over its lifecycle; aim for under 200 ms.
These are not isolated; improving one often helps with others, but each has its challenges.
H2. Why They Matter for SEO & UX
- Google uses Core Web Vitals in its Page Experience ranking signals.
- Poor scores can lead to higher bounce rates and lost conversions.
- Improving them enhances user satisfaction — pages feel faster, smoother, more stable.
10 Quick Wins to Improve LCP, CLS & INP
Below are 10 practical strategies (quick wins) you can start implementing immediately. These are based on best practices and recent updates in 2025 optimization strategies.
1. Prioritize the LCP Element with fetchpriority="high"
Mark the image or element that you expect to be the Largest Contentful Paint with fetchpriority="high" so that the browser loads it earlier. This hints the browser to prioritize that resource.
Best practices:
- Ensure that element is in your initial HTML, not added later via JavaScript.
- Avoid lazy-loading for the LCP element.
- Use
preloadtoo if possible for large images, with correct attributes.
2. Reduce Server Response Time / Use a CDN
Slow server response (Time to First Byte, TTFB) delays everything. A faster server or edge servers (CDN) can dramatically improve LCP.
Tips:
- Use a high-performance host or server refinement (e.g. caching, upgraded plan).
- Use a CDN to deliver static assets from nodes close to the user.
- Cache dynamic content where safe.
3. Inline Critical CSS & Defer Non-Critical CSS
Render-blocking CSS delays page rendering. Inline only what’s needed to style the above-the-fold content, and defer the rest.
Steps:
- Extract critical CSS for initial view.
- Inline it in the
<head>. - Use
rel="preload"or load the full stylesheet later asynchronously.
4. Lazy-Load Offscreen Images & Videos
Delay loading images/videos that are not in the viewport until the user scrolls. This reduces blocking for the LCP.
Cautions:
- Don’t lazy-load images that might become the LCP.
- For videos, set proper
posteror preload first frame if it becomes LCP.
5. Reserve Space for Dynamic Elements to Prevent CLS
CLS issues happen when elements shift after load — like images without dimensions, iframes, ads, or injected content.
Fixes:
- Always specify
widthandheightor aspect ratio containers. - For ads, embeds, or iframes, allocate a reserved container size.
- Avoid inserting layout elements above others after load (e.g. banners).
- Use
transformovertop/leftto animate positions.
6. Defer or Async JavaScript & Minimize Main Thread Work
Heavy JavaScript execution slows interactivity and impacts INP.
Recommendations:
- Use
asyncordeferfor script tags. - Break up long-running tasks, use Web Workers for heavy computations.
- Avoid unnecessary polyfills or third-party scripts on initial load.
7. Optimize Font Loading
Fonts are invisible but critical. Poor font loading can block text display or cause layout shifts (CLS).
Techniques:
- Preload critical fonts with
<link rel="preload" as="font">. - Use
font-display: swapto allow fallback and avoid invisible text. - Subset fonts (only include needed characters).
- Consider system fonts for faster rendering.
8. Use Efficient Media Formats & Compression
Modern formats like WebP, AVIF, or compressed images/videos reduce payload size and improve LCP.
Tips:
- Convert large JPEG/PNG to WebP/AVIF.
- Compress images properly.
- Use responsive images (
srcset) to serve appropriate sizes per device.
9. Avoid Layout Shifts During User Interaction
Because INP includes interaction-based layout shifts, ensure that when users click, scroll, or interact, the layout doesn’t move.
Tips:
- Don’t inject or reposition elements in response to user events unless necessary.
- Use stable UI patterns (buttons, menus) that don’t shift.
- For collapsible components, preserve height/space during transitions.
10. Monitor & Test Continuously (Field + Lab)
Quick wins are great, but continuous testing ensures you don’t regress. Use both real-user (field) and lab data.
Tools to use:
- Google Search Console – Core Web Vitals report.
- PageSpeed Insights / Lighthouse – Lab + field data.
- Web Vitals Chrome extension / Real User Monitoring (RUM)
- Track metrics over time, segment by device types, track changes after deploy.
Implementation Plan & Checklist
Here’s how to roll out these optimizations step by step:
- Baseline Audit: Use Google Search Console and PageSpeed Insights to gather current LCP, CLS, INP scores.
- Pick top pages: Focus on pages that drive traffic or conversions.
- Apply Quick Wins: Start with image/font optimizations, defer JS, reserve layout space.
- Re-test after each change to catch regressions.
- Roll out to rest of site once top pages are stable.
- Monitor continuously, especially after new features or content changes.
Frequently Asked Questions (FAQ)
Q1: What are good thresholds for LCP, CLS, and INP?
- LCP: ≤ 2.5 seconds
- CLS: ≤ 0.1
- INP: ≤ 200 milliseconds
Q2: Why did Google replace FID with INP?
INP is considered a more holistic metric because it measures responsiveness for all user interactions over the page’s lifetime, not just the first one.
Q3: Can lazy-loading images harm LCP?
Yes, if you lazy-load the element that becomes the LCP. Avoid lazy-loading that critical element.
Q4: How often should I test my site?
At least weekly for key pages, and after each major content or code update.
Q5: Do good Core Web Vitals guarantee high ranking?
No — they are one part of Google’s page experience signals. Good content, authority, and relevance remain critical.
Conclusion + Call-to-Action
Core Web Vitals can seem technical, but by applying these 10 quick wins, you can make measurable improvements to LCP, CLS, and INP — boosting user experience, engagement, and search performance.
👉 Call-to-Action: Pick one page, apply one or two of these strategies today, and track your results. Over time, layer the others. Performance is a journey — not a one-time fix.
