What: This guide shares five practical ways to improve Core Web Vitals and enhance website performance.
Who: Website owners, marketers, SEO teams, and developers looking to improve rankings and UX.
Why: Google uses Core Web Vitals as a ranking signal. Slow or unstable pages can hurt visibility and conversions.
How: Step-by-step fixes for LCP, CLS, FID, and INP, plus tools to monitor performance.
In This Article
Share On:
Improve user experience and boost SEO by fixing the performance metrics Google cares about most.
Search engines have become more focused on how users experience your website, not just what it says. Core Web Vitals are Google’s way of measuring that experience. These metrics track how fast your site loads, how stable it appears while loading, and how quickly users can interact with it.
In 2025, Core Web Vitals are not just technical details. They are part of the page experience signal that can influence where your site ranks in search results. If your site feels slow, shifts around when loading, or delays user input, it may lose both traffic and credibility.
The good news is that improving Core Web Vitals does not require a complete site rebuild. In this blog, we will explain what these metrics mean, why they matter, and show you five simple and effective fixes that can boost your site’s performance and visibility.
Fix Core Web Vitals Issues and Rank Higher
Learn how to optimise site speed, stability, and responsiveness for a better user experience and stronger SEO performance.
What Are Core Web Vitals? A Quick Guide
Core Web Vitals are a set of user-focused metrics that measure the quality of experience on your website. Introduced by Google, these metrics reflect how quickly your page loads, how visually stable it is, and how responsive it feels to user actions. They apply to all websites and directly influence search rankings.
Here are the main metrics you need to know:
Metric
What It Measures
Good Score
Largest Contentful Paint (LCP)
Loading speed of the main content visible to the user
Under 2.5 seconds
Cumulative Layout Shift (CLS)
Visual stability as the page loads (avoiding sudden shifts)
Less than 0.1
First Input Delay (FID)
Time from first user interaction to browser response
Under 100 milliseconds
Interaction to Next Paint (INP)
A new metric replacing FID, offering a more complete view of interactivity
Under 200 milliseconds
In 2024, Google began shifting from FID to INP as the primary measure of input responsiveness.
These metrics are measured using both lab tools (for developers) and real-world user data. Websites that meet the recommended thresholds across all three metrics are considered to have a good page experience.
Why Core Web Vitals Impact Your Google Rankings
Core Web Vitals are part of Google’s page experience update, which evaluates how users interact with your content beyond just keywords and links. Since this update became a ranking factor in 2021, performance metrics like LCP, CLS, and INP have played a supporting role in how pages are ranked, especially when multiple results are otherwise equal in content relevance.
Google’s goal is to prioritise websites that offer not only valuable information but also a smooth and responsive user experience. This means that pages loading slowly, shifting visually during load, or responding poorly to user actions are considered less helpful, even if their content is strong.
Why Each Metric Matters to Google and Users
Largest Contentful Paint (LCP) A slow LCP means users are left staring at a blank or incomplete page. This increases bounce rates and reduces the chance of engagement or conversion.
Cumulative Layout Shift (CLS) Unexpected layout shifts frustrate users, especially on mobile devices. Pages that move buttons or text during load can cause accidental clicks or reduce trust.
Interaction to Next Paint (INP) Replacing FID, INP tracks how responsive your site feels when users interact with it. A lag between a user clicking and seeing something happen signals a poor experience.
Google uses these metrics across groups of similar pages. If multiple product or blog pages perform poorly on CWV, it can affect the entire group’s visibility.
Mobile Experience Is Key
Because Google uses mobile-first indexing, your site’s mobile Core Web Vitals have a direct impact on how it ranks, even in desktop results. A site that performs well on desktop but poorly on mobile may still lose search visibility if mobile scores are not optimised.
Real-World Example
Many e-commerce websites that improved LCP by compressing product images and reducing third-party scripts saw measurable increases in rankings and revenue. In industries where speed and usability directly affect sales, small performance gains lead to significant SEO and business outcomes.
With Core Web Vitals affecting both how users experience your site and how search engines evaluate it, improving these metrics is no longer optional. It is a vital part of SEO in 2025.
5 Simple Fixes to Improve Core Web Vitals
Improving Core Web Vitals does not always require a complete website redesign. In many cases, a few targeted fixes can significantly boost performance and user experience. These five actions are some of the most effective and accessible ways to improve your LCP, CLS, and INP scores.
Fix 1: Optimise and Compress Images
Large, uncompressed images are one of the most common causes of poor LCP scores. To improve loading speed:
Use next-gen image formats like WebP or AVIF
Resize images to the exact dimensions needed on the page
Apply image compression tools such as TinyPNG or Squoosh
Serve responsive images with the <picture> tag or srcset attribute
Impact: Improves Largest Contentful Paint (LCP), especially on image-heavy landing or product pages.
Fix 2: Eliminate Render-Blocking Resources
Render-blocking scripts delay page loading and interactivity. To reduce their impact:
Defer non-essential JavaScript using defer or async attributes
Minify CSS and JavaScript files to reduce size
Inline critical CSS for above-the-fold content
Remove unused third-party scripts where possible
Impact: Improves both LCP and Interaction to Next Paint (INP) by reducing delays in rendering key elements.
Fix 3: Set Explicit Width and Height for Media
Unexpected layout shifts are often caused by images, videos, or iframes loading without predefined dimensions. To prevent this:
Always set width and height attributes in your HTML
Reserve space for ads or dynamic content blocks
Avoid inserting large elements above existing content after page load
Impact: Reduces Cumulative Layout Shift (CLS) and creates a smoother visual experience.
Fix 4: Reduce and Optimise Third-Party Scripts
Third-party tools like chat widgets, ad trackers, or embedded video players can slow down load time and interaction speed. To manage their impact:
Audit and remove unused or duplicate scripts
Load scripts asynchronously where possible
Self-host critical scripts, such as fonts or analytics, for better control
Impact: Improves INP and overall site responsiveness, especially on mobile devices.
Fix 5: Use a Content Delivery Network (CDN) and Browser Caching
Serving your content from geographically closer servers and reducing repeated downloads helps improve page load times. To implement:
Use a CDN like Cloudflare, Fastly, or BunnyCDN
Enable browser caching through server configurations
Compress assets using Gzip or Brotli
Impact: Improves LCP and INP across users in different locations, making performance more consistent.
Each of these fixes can be measured and monitored using Google’s performance tools, which we will cover in the next section.
Which Tools Help You Monitor and Improve Core Web Vitals?
To improve Core Web Vitals, you first need reliable data. Google provides a set of free tools that help track loading speed, layout shifts, and input responsiveness. These tools combine simulated testing with real-world usage data to give you a complete picture of your site’s performance.
Below are the four most effective and distinct tools for monitoring Core Web Vitals:
PageSpeed Insights analyses individual URLs using both lab data (simulated performance) and field data (real user metrics from Chrome). It highlights LCP, CLS, and INP scores separately for mobile and desktop.
Use it to:
Measure Core Web Vitals for any public URL
Identify performance bottlenecks
Prioritise optimisations based on real-user impact
Lighthouse is built into the Chrome browser and provides detailed performance reports. It simulates how your page performs under average network conditions and flags elements that slow down rendering or cause layout shifts.
How to use it:
Open your website in Chrome
Right-click and select Inspect
Navigate to the Lighthouse tab
Choose either mobile or desktop, then run the audit
If your site is verified in Search Console, you can access the Core Web Vitals report, which shows how groups of URLs are performing based on real-world Chrome user data.
Use it to:
Monitor site-wide Core Web Vitals trends
Detect groups of pages failing LCP, CLS, or INP thresholds
CrUX provides anonymised, real-world performance data from Chrome users. It powers the field data seen in tools like PageSpeed Insights and Search Console.
Use it to:
Benchmark your site’s performance against others in your industry
Analyse large-scale trends in user experience
Understand how your site performs across different devices and networks
By using these tools together, you can monitor both individual pages and overall site health, identify what needs fixing, and measure the impact of your optimisations over time.
Growth Plan
Looking to improve your website’s performance across all devices?
Use upGrowth’s Core Web Vitals Audit checklist or connect with our growth team to explore practical improvements for your site.
Core Web Vitals are not just technical scores; they reflect how users experience your website. In 2025, improving these metrics is one of the simplest ways to enhance both your SEO performance and user satisfaction.
Fixes like compressing images, stabilising layouts, and reducing script delays can lead to faster loading times, smoother browsing, and higher search visibility. When these improvements are applied consistently across your site, they also lead to better retention and conversion outcomes.
At upGrowth, we encourage businesses to treat performance optimisation as an ongoing part of digital strategy, not just a one-time fix. Core Web Vitals are a key indicator of how well your website meets user expectations, and fixing them should be a priority for anyone serious about growth.
Mastering Core Web Vitals
Optimizing User Experience and Search Performance at upGrowth.in
LCP: Speed as a Growth Lever
Largest Contentful Paint (LCP) measures how fast the main content of a page loads. For Fintech and SaaS, speed equals trust. By optimizing server response times, leveraging modern image formats, and prioritizing critical CSS, brands can ensure users aren’t met with a blank screen, directly reducing bounce rates and improving conversion potential.
INP: Responsive User Journeys
Interaction to Next Paint (INP) replaces FID to measure overall page responsiveness. A laggy interface during a financial transaction or signup creates friction. Fixing interactivity involves minimizing main-thread work and breaking up long JavaScript tasks, ensuring the application feels snappy and reliable across all device types.
CLS: Preventing Layout Frustration
Cumulative Layout Shift (CLS) measures visual stability. Unexpected shifts—like an ad pushing a button just as a user clicks—damage the user experience. By specifying size attributes for images/videos and ensuring dynamic content doesn’t disrupt existing elements, brands create a stable environment that fosters user confidence and retention.
FAQs
1. How can I quickly improve my website’s Largest Contentful Paint (LCP)? You can improve LCP by compressing large images, using next-gen formats like WebP, and reducing render-blocking scripts that delay content from loading.
2. What are the easiest ways to reduce Cumulative Layout Shift (CLS)? To reduce CLS, always set fixed width and height for images and videos, avoid inserting new content above the fold during load, and minimise dynamic layout changes.
3. How does Interaction to Next Paint (INP) affect user experience and rankings? INP measures how quickly a page responds to user interactions. A high INP score means your site feels unresponsive, which can lower engagement and potentially affect your Google rankings.
4. Can fixing Core Web Vitals boost my position on Google in 2025? Yes. While content remains a core ranking factor, Core Web Vitals influence your site’s page experience score. Better performance can give you an edge in competitive SERPs.
5. Which tools can help monitor and improve Core Web Vitals? Trusted tools include PageSpeed Insights, Lighthouse in Chrome DevTools, Google Search Console, and the Chrome User Experience Report (CrUX).
6. Is there a difference between lab data and field data in Core Web Vitals? Yes. Lab data is based on simulated conditions and helps developers test performance. Field data reflects real-user experience and is what Google uses to evaluate ranking impact.
7. How often should I audit my website’s Core Web Vitals? Monthly audits are ideal for most websites. However, high-traffic or e-commerce sites should monitor them weekly, especially after making design, speed, or layout changes.
8. Can I use ChatGPT to interpret my Core Web Vitals data? Yes. You can input your PageSpeed Insights report into ChatGPT and ask for a simplified explanation or a step-by-step action plan based on your site’s metrics.
9. How can Gen AI tools assist in fixing Core Web Vitals issues? Generative AI can help you identify performance bottlenecks, summarise audit reports, and recommend code optimisations, especially if you integrate it with development workflows or analytics dashboards.
10. Are Core Web Vitals equally important on mobile and desktop? Yes, but Google evaluates performance using mobile-first indexing. This means mobile Core Web Vitals scores typically have a greater influence on your search rankings.
For Curious Minds
Core Web Vitals quantify user experience by measuring how fast your page loads, its visual stability, and its responsiveness to interaction. Prioritizing them is crucial because Google integrates these metrics into its page experience signal, directly influencing your site’s ability to rank, retain visitors, and drive conversions.
These metrics translate technical performance into tangible user perceptions. A poor score in any area signals a frustrating experience, which Google aims to de-prioritize in search results. The key metrics are:
Largest Contentful Paint (LCP): This measures loading performance. To pass, your main content should appear in under 2.5 seconds, assuring users that the page is working quickly.
Cumulative Layout Shift (CLS): This tracks visual stability. A score below 0.1 indicates that page elements are not unexpectedly moving, preventing accidental clicks.
Interaction to Next Paint (INP): This assesses responsiveness. An INP under 200 milliseconds ensures the interface reacts promptly to user actions like clicks or taps.
Improving these scores is a direct investment in user satisfaction, which is becoming inseparable from effective SEO strategy. Understanding how to diagnose and fix shortfalls is the first step toward building a more competitive online presence.
Interaction to Next Paint (INP) offers a more complete view of a page’s responsiveness by measuring the latency of all user interactions, not just the first one like First Input Delay (FID) did. This change signifies Google's deeper focus on the entire user journey, penalizing sites that feel sluggish after the initial load.
While FID measured only the delay before the browser could start processing the first input, INP assesses the full lifecycle of an interaction, from user action to the next visual update. A good INP score is under 200 milliseconds. For developers, this shift requires a broader optimization strategy:
Focus on the entire user session: Optimizations must now account for clicks, taps, and key presses that happen at any point, not just at the beginning.
Reduce main-thread work: Long-running JavaScript tasks are a common cause of high INP. Breaking up these tasks allows the browser to respond to user inputs more quickly.
Audit third-party scripts: Scripts for ads, analytics, or chat widgets often compete for main-thread time and can significantly delay interactions.
This evolution from FID to INP means that a continuously smooth and interactive experience is now a measured component of technical SEO. To learn how to audit your scripts and minimize main-thread work, explore the detailed fixes discussed within.
Improving Core Web Vitals directly correlates with better business outcomes because faster, more stable sites enhance the user experience, leading to higher engagement and conversions. E-commerce sites, in particular, see measurable gains because speed and usability are critical factors in a user's decision to make a purchase.
The connection is proven through both Google's ranking algorithm and user behavior data. When Google made page experience a ranking factor in 2021, it confirmed that sites providing a better experience could gain a competitive edge. Real-world examples reinforce this:
Improved Rankings: Many online retailers that focused on achieving an LCP under 2.5 seconds by compressing product images and deferring non-critical scripts saw a tangible lift in their search engine rankings for competitive keywords.
Reduced Bounce Rates: A fast LCP keeps users on the page, while a low CLS (below 0.1) prevents frustrating mis-clicks on 'add to cart' or 'buy now' buttons, reducing cart abandonment.
Increased Revenue: For industries where conversions happen quickly, even small performance gains translate to significant revenue increases by reducing friction in the purchasing journey.
Optimizing these metrics is not just a technical task, it is a proven strategy for driving growth. The full analysis provides further examples of how specific fixes lead to these positive business results.
The most common mistake causing a high Cumulative Layout Shift (CLS) score is failing to specify dimensions for media elements like images, videos, and ad containers. High-performing websites avoid this by reserving space for these elements in the HTML, ensuring the layout remains stable as the page loads.
When a browser doesn't know the size of an element, it cannot allocate the correct amount of space for it. Once the element finally loads, it pushes other content down the page, causing a jarring shift. To solve this and achieve a CLS score of less than 0.1, you should:
Set `width` and `height` attributes: Always include width and height attributes on your `<img>` and `<video>` tags. The browser can then use these to calculate the aspect ratio and reserve the necessary space.
Reserve space for dynamic content: For elements like ads or embedded widgets, use CSS to define a container with a fixed size (e.g., using `min-height`). This creates a placeholder that prevents content from shifting when the ad loads.
Avoid inserting content above existing content: Do not dynamically inject banners or notices at the top of the page after it has started rendering unless you have already reserved space for them.
By declaring content dimensions upfront, you create a predictable and trustworthy user experience. Discover other common layout issues and their solutions by reviewing our complete optimization checklist.
Because Google primarily uses the mobile version of your site for indexing and ranking, your mobile Core Web Vitals scores have a direct and significant impact on search visibility across all devices, including desktop. Even if your site performs flawlessly on a desktop, poor mobile scores for LCP, CLS, and INP can limit your overall SEO potential.
This mobile-first indexing approach means your optimization priorities must be centered on the mobile user experience. A slow, unresponsive mobile site is seen by Google as a poor experience overall, which can demote your pages in search results regardless of the user's device. Your primary focus should be on:
Fast Mobile Loading: Aim for an LCP under 2.5 seconds on mobile connections by optimizing images and eliminating render-blocking resources.
Stable Mobile Layouts: Ensure a CLS score below 0.1 by setting explicit dimensions for all media, as layout shifts are more disruptive on smaller screens.
Quick Mobile Interactions: Achieve an INP under 200 milliseconds by minimizing the impact of third-party scripts, which are often more resource-intensive on mobile devices.
Treating mobile performance as the foundation of your SEO strategy is no longer optional. The full article explores how tools like PageSpeed Insights can help you diagnose and compare mobile versus desktop performance.
Lab data and field data provide two distinct but complementary views of your site's performance; one is for diagnostics, and the other reflects real-world impact. While lab data is excellent for debugging, you should ultimately trust field data more, as it represents what your actual users experience and is what Google uses for ranking.
Understanding their strategic roles is key to effective optimization.
Lab Data (e.g., Lighthouse): This is generated under controlled, simulated conditions (e.g., a specific device and network speed). It is perfect for developers to test changes, identify performance bottlenecks, and get immediate feedback before deploying updates. Its main purpose is diagnostic.
Field Data (e.g., CrUX, PageSpeed Insights): This is collected from real Chrome users who opt-in to sharing anonymized data. It reflects performance across a wide range of devices, network conditions, and locations. This data, which populates the Core Web Vitals report in Google Search Console, is what Google uses as a ranking signal. Its purpose is evaluative.
Use lab data to identify and fix issues, but use field data to validate the real-world success of those fixes. The complete guide explains how to use both types of data together to create a robust performance monitoring workflow.
Third-party scripts are a leading cause of poor Interaction to Next Paint (INP) because they compete for processing power and can block the main thread, delaying your site's response to user input. You can mitigate their impact by optimizing how and when they load, rather than removing them entirely.
A systematic audit and a few loading strategy adjustments can significantly improve your INP score, which should be under 200 milliseconds. Try these proven techniques:
Audit and Remove Unused Scripts: First, identify and eliminate any scripts that are no longer providing value. This is the simplest and most effective step.
Load Scripts Asynchronously: Use the `async` or `defer` attributes on your `` tags. `async` allows the script to load in the background without blocking rendering, while `defer` executes the script after the document has been parsed.
Delay Loading of Non-Essential Scripts: For tools that are not needed immediately, such as chat widgets or social media feeds, delay their loading until after the user starts interacting with the page (e.g., by scrolling or clicking).
Self-Host Where Possible: For critical resources like fonts or analytics scripts, hosting them on your own server or CDN (like BunnyCDN) can reduce DNS lookup times and give you more control over caching.
By managing the priority and timing of these scripts, you can preserve functionality while ensuring your site remains responsive. For more advanced techniques, consider the detailed script optimization methods discussed further.
Render-blocking resources, primarily CSS and JavaScript, directly harm both Largest Contentful Paint (LCP) and Interaction to Next Paint (INP) by forcing the browser to pause page rendering until they are downloaded and processed. This delay leaves users waiting for content to appear and prevents the page from responding to their interactions.
Effectively managing these resources is critical for a high-performance website. Here are four code-level fixes you can implement:
Defer Non-Critical JavaScript: Add the `defer` attribute to your `` tags for any JavaScript that is not essential for the initial page view. This tells the browser to download the script in the background and execute it only after the main HTML is parsed.
Inline Critical CSS: Identify the minimum CSS required to style the above-the-fold content and place it directly within a `` block in the `` of your HTML. This allows the browser to render visible content immediately.
Load Other CSS Asynchronously: For the remaining non-critical CSS, use a technique to load it asynchronously so it does not block the initial render.
Minify Files: Use build tools to minify your CSS and JavaScript files, which removes unnecessary characters and reduces their overall size, speeding up download times.
These optimizations ensure that the browser can render visible content and become interactive as quickly as possible. More advanced strategies, including code splitting, are available for those looking to further refine their site's performance.
For a blog with a global audience, combining a Content Delivery Network (CDN) with effective browser caching is a powerful strategy for improving LCP and INP. A CDN reduces network latency by serving assets from locations closer to your users, while caching reduces the number of requests the browser needs to make for repeat visits.
This two-pronged approach ensures both first-time and returning visitors have a fast, responsive experience. Here is how they work together:
CDN for Global Speed (Improves LCP): A CDN like Cloudflare or Fastly stores copies of your static assets (images, CSS, JS) on servers around the world. When a user visits your blog, content is delivered from the nearest server, drastically cutting down load times and improving your LCP, which should be under 2.5 seconds.
Browser Caching for Repeat Visits (Improves LCP & INP): By setting proper caching headers on your server, you instruct the user's browser to store local copies of assets. On subsequent page views, the browser can load these files directly from disk instead of re-downloading them, making the site feel almost instant.
Asset Compression: Most CDNs also offer features like Gzip or Brotli compression, which further reduce file sizes before they are sent to the user, enhancing both LCP and INP.
This combination creates a consistently fast experience for all users, regardless of their location. Explore the full guide to see how to configure caching headers and select the right CDN for your needs.
Core Web Vitals metrics will continue to evolve to better capture the nuances of user experience, as seen with the shift from FID to the more comprehensive INP metric. To future-proof your site, your team should focus on the underlying principles of web performance rather than just optimizing for current thresholds.
Google's goal is to reward sites that are genuinely fast, responsive, and stable. A proactive strategy should include:
Focus on Perceived Performance: Instead of just chasing numbers like an LCP under 2.5 seconds, concentrate on how fast the user feels the site is. This means prioritizing the loading of visible content and ensuring immediate feedback for interactions.
Maintain a Performance Budget: Establish strict limits on page weight, image sizes, and the number of third-party scripts. Regularly audit your site to ensure these budgets are not exceeded as new features are added.
Automate Performance Monitoring: Integrate tools like Lighthouse into your development workflow to automatically test every code change. This prevents performance regressions from ever reaching production.
Stay Informed: Keep up with announcements from the Google Search and Chrome developer teams, as they often signal upcoming changes to ranking factors and performance metrics.
By building a culture of performance, your site will be well-prepared to meet not only today's Core Web Vitals but also whatever metrics come next.
For a SaaS business, strong Core Web Vitals on content marketing pages directly contribute to lead generation by enhancing user trust, improving search visibility, and reducing friction in the conversion funnel. A fast and stable site signals professionalism and reliability, which are critical attributes when a potential customer is evaluating your software.
While not transactional like an e-commerce page, the performance of your informational content plays a key role in nurturing prospects. Here is how:
Increased Organic Traffic: Google's page experience signal helps high-performing content rank better. Achieving a good LCP (under 2.5 seconds) and INP (under 200 ms) can boost the visibility of your blog posts and case studies, attracting more top-of-funnel traffic.
Higher Engagement: A responsive, stable reading experience encourages visitors to spend more time on your site, consume more content, and develop a stronger affinity for your brand.
Improved Conversion Rates: When a user decides to click a call-to-action like 'Request a Demo' or 'Download Whitepaper', a low INP ensures the site responds instantly, minimizing drop-off at the most critical point of conversion.
A seamless user experience on your content pages builds the confidence needed for a visitor to take the next step. Improving these metrics is a tangible way to optimize your entire marketing funnel.
Amol has helped catalyse business growth with his strategic & data-driven methodologies. With a decade of experience in the field of marketing, he has donned multiple hats, from channel optimization, data analytics and creative brand positioning to growth engineering and sales.
