Optimizing eCommerce Businesses since 2016Core Web Vitals, a set of performance metrics introduced by Google, have become a key ranking factor in search engine results. These metrics focus on aspects of website speed, responsiveness, and visual stability, and optimizing them can significantly improve both your site’s SEO performance and user experience.
This step-by-step guide will explain what Core Web Vitals are, why they matter, and how you can optimize your website to meet these metrics. By the end of this guide, you’ll have actionable insights and techniques to boost your site’s speed and improve Core Web Vitals scores.
LCP, FID & CLS Scores
1. What Are Core Web Vitals?
Core Web Vitals are a set of metrics that measure user experience with regard to three key aspects of web performance:
- Largest Contentful Paint (LCP): Measures how long it takes for the largest content element on a webpage to load. This could be an image, a video, or a large block of text.
- First Input Delay (FID): Measures the time it takes for the page to respond after a user first interacts with it (e.g., clicks a button, taps a link).
- Cumulative Layout Shift (CLS): Measures the visual stability of a page and how much elements move around as the page loads.
Table: Core Web Vitals Benchmarks
| Metric | Good | Needs Improvement | Poor |
|---|---|---|---|
| Largest Contentful Paint (LCP) | ≤ 2.5 seconds | 2.5 – 4.0 seconds | > 4.0 seconds |
| First Input Delay (FID) | ≤ 100 milliseconds | 100 – 300 milliseconds | > 300 milliseconds |
| Cumulative Layout Shift (CLS) | ≤ 0.1 | 0.1 – 0.25 | > 0.25 |
By optimizing your site to meet the recommended thresholds for these metrics, you can improve user satisfaction and boost your SEO rankings.
2. Why Core Web Vitals Matter
Google uses Core Web Vitals as part of its Page Experience update, meaning they directly impact your site’s ranking in search results. If your website provides a faster and smoother user experience, Google will prioritize it in its rankings. Sites that neglect these metrics may struggle to rank, even if they have strong content and backlinks.
Additionally, improving Core Web Vitals has a significant impact on user experience. Fast and responsive websites keep users engaged, lower bounce rates, and increase conversions, while slow and clunky websites drive users away.
3. How to Measure Your Core Web Vitals
Before optimizing, you need to measure your website’s Core Web Vitals performance. Fortunately, there are several tools available that provide insights into these metrics:
- Google PageSpeed Insights: This free tool evaluates your site’s performance and provides detailed feedback on LCP, FID, and CLS, along with suggestions for improvement. Access the tool here.
- Google Search Console: In the “Core Web Vitals” report, you can see which URLs on your site need improvement. It highlights pages that have poor performance for LCP, FID, and CLS. More information here.
- Lighthouse: An open-source tool available in Chrome DevTools, Lighthouse audits the performance, accessibility, and SEO of your website. You can generate a report and identify how to improve Core Web Vitals using Lighthouse.
Example of a Core Web Vitals Report:
| Page | LCP | FID | CLS | Recommendation |
|---|---|---|---|---|
| Home Page | 3.1 sec | 200 ms | 0.15 | Optimize images and reduce JS |
| Product Page | 2.4 sec | 150 ms | 0.08 | Good performance |
| Blog Post | 4.5 sec | 350 ms | 0.30 | Lazy load images, reduce CLS |
Once you’ve identified which pages need attention, you can start optimizing them to improve the metrics.and making it enticing, you increase your chances of ranking higher and attracting clicks.
4. Improving Largest Contentful Paint (LCP)
What is LCP?
Largest Contentful Paint (LCP) measures how long it takes for the largest visible element (image, video, or block of text) to load on the screen. A slow LCP can be caused by factors like slow server response times, render-blocking resources, and unoptimized images.
How to Optimize LCP:
a. Optimize and Compress Images
Unoptimized images are one of the main causes of poor LCP. Large image files can significantly slow down your page’s load time.
- Use Next-Gen Image Formats: Convert your images to WebP, which provides better compression without sacrificing quality.
- Compress Images: Use tools like TinyPNG or ImageOptim to reduce the file size of your images.
- Lazy Loading: Implement lazy loading so that images below the fold aren’t loaded until the user scrolls to them.
b. Improve Server Response Time
Slow servers result in slower loading pages, which directly impacts LCP.
- Use a Content Delivery Network (CDN): CDNs distribute your content across multiple servers worldwide, serving your site from the nearest server to the user. This reduces latency and speeds up content delivery.
- Enable Caching: Use browser caching to store static files (like CSS, JavaScript, and images) in a user’s browser so that they don’t have to be reloaded every time they visit your site.
c. Eliminate Render-Blocking Resources
Resources such as CSS and JavaScript files can block the rendering of your page, delaying LCP.
- Minify CSS and JavaScript: Use tools like Minify or CSSNano to remove unnecessary characters, comments, and spaces from your code to reduce its size.
- Defer JavaScript: Use the
deferattribute to load JavaScript only after the initial page content has been rendered.
Chart: Common LCP Optimization Techniques
| Technique | Impact on LCP | Complexity |
|---|---|---|
| Optimize and compress images | High | Low |
| Use a CDN | High | Medium |
| Minify CSS and JavaScript | Medium | Low |
| Defer JavaScript | Medium | Medium |
5. Improving First Input Delay (FID)
What is FID?
First Input Delay (FID) measures how long it takes for the page to respond to the user’s first interaction (click, tap, scroll). High FID scores are typically caused by heavy JavaScript execution, which delays the page’s interactivity.
How to Optimize FID:
a. Reduce JavaScript Execution
Long-running JavaScript tasks can delay interactivity. To improve FID, minimize and optimize your JavaScript.
- Break Up Long Tasks: Break up long-running JavaScript tasks into smaller, asynchronous tasks. Use
setTimeoutorrequestIdleCallbackto ensure that the main thread remains responsive. - Lazy Load JavaScript: Load only the JavaScript required for initial page load, deferring any non-essential JavaScript.
b. Optimize Web Workers
Web Workers allow you to run JavaScript in the background without blocking the main thread.
- Offload Heavy JavaScript Tasks: Use Web Workers to offload heavy computations from the main thread, improving the page’s responsiveness and reducing FID.
c. Reduce Third-Party Scripts
Third-party scripts (such as analytics, social media embeds, or ads) can delay the execution of your own JavaScript.
- Limit the Number of Third-Party Scripts: Remove any unnecessary third-party scripts or widgets from your site to minimize their impact on FID.
Chart: FID Optimization Strategies
| Optimization Technique | Impact on FID | Difficulty Level |
|---|---|---|
| Reduce JavaScript execution | High | Medium |
| Use Web Workers | Medium | High |
| Limit third-party scripts | High | Low |
6. Improving Cumulative Layout Shift (CLS)
What is CLS?
Cumulative Layout Shift (CLS) measures how much content on the page shifts unexpectedly while loading. This can be caused by images or ads loading late or fonts that render differently after loading.
How to Optimize CLS:
a. Set Explicit Size for Images and Ads
When you don’t specify the size for images or ads, the browser doesn’t know how much space to allocate for them, causing content to shift when they load.
- Set Width and Height: Always define the width and height attributes for images, videos, and ads in your HTML or CSS so the browser reserves the space before they load.
b. Preload Important Fonts
Loading custom fonts can cause content shifts if the fallback font is replaced after the page is rendered.
- Preload Fonts: Use the
rel="preload"attribute in the<link>tag to load critical fonts early.
c. Avoid Inserting Content Above the Fold
Inserting new content above existing content while the page is loading can cause layout shifts.
- Insert Content Below Existing Content: Ensure that dynamic content, such as banners or ads, is loaded below the fold to prevent CLS issues.
Chart: CLS Reduction Techniques
| Optimization Technique | Impact on CLS | Complexity |
|---|---|---|
| Set image/ads sizes explicitly | High | Low |
| Preload important fonts | Medium | Medium |
| Avoid inserting content above fold | High | Low |
rt a vegetable garden” and provides a compelling reason for users to click on the link.
7. Monitoring and Maintaining Core Web Vitals
After optimizing your site for LCP, FID, and CLS, it’s important to regularly monitor these metrics and make continuous improvements. Use the tools mentioned earlier (Google PageSpeed Insights, Lighthouse, Google Search Console) to track your progress and identify any new issues that arise.
Key Metrics to Track:
- LCP (Largest Contentful Paint): How quickly the main content loads.
- FID (First Input Delay): How responsive your site is to user interaction.
- CLS (Cumulative Layout Shift): How stable your content layout is during loading.
Regular monitoring will ensure that your site remains optimized for speed and performance, providing a smooth experience for your users and maintaining your SEO rankings.
Speeding Up Core Web Vitals
Optimizing your website for Core Web Vitals is essential for providing a fast, responsive, and stable experience to users, while also improving your SEO performance. By following the steps outlined in this guide—optimizing images, minimizing JavaScript, improving server response times, and ensuring layout stability—you can significantly enhance your site’s performance and meet Google’s Core Web Vitals benchmarks.
Focus on continuous monitoring and optimization to stay ahead of potential issues, ensuring that your website remains fast and user-friendly over time. A faster, more responsive site will not only improve your rankings but also increase user engagement and conversions.
For the modern business, paying attention to Core Web Vitals returns in the form of higher rankings, more traffic, and increased conversions.
Looking to improve Core Web Vitals? Contact our team for affordable help.