You've probably heard about Core Web Vitals and know they're important for your website, but what are they exactly? And more importantly, how do you make sure your website "passes" them? If you're new to Core Web Vitals, this guide explains everything in simple terms. You'll learn what LCP, CLS, and FID mean, why Google cares about them, what scores you need to pass, and practical steps to improve your scores. By the end of this guide, you'll understand Core Web Vitals and know exactly what to do to pass Google's requirements.
What Are Core Web Vitals?
Core Web Vitals are three specific measurements that Google uses to evaluate how good the user experience is on your website. Think of them as a report card that Google gives your website based on how real users experience it.
Why Google Created Core Web Vitals
Google wants to show users websites that provide a great experience. If your website is slow, jumps around while loading, or feels unresponsive, users have a bad experience. Core Web Vitals help Google identify which websites provide good experiences and which don't.
The Three Metrics
There are three Core Web Vitals metrics:
- LCP (Largest Contentful Paint): Measures how fast your main content loads
- CLS (Cumulative Layout Shift): Measures how stable your page is (does it jump around?)
- FID (First Input Delay): Measures how responsive your site feels when users interact with it
Google uses all three metrics together to evaluate your website's user experience. To "pass" Core Web Vitals, you need to meet Google's standards for all three.
Why Core Web Vitals Matter
Understanding why Core Web Vitals matter helps motivate you to improve them:
1. They Affect Search Rankings
Google uses Core Web Vitals as ranking factors. Websites with good Core Web Vitals scores rank higher in search results than websites with poor scores. This directly impacts how many people find your website through Google.
2. They Measure Real User Experience
Core Web Vitals measure what real users actually experience. Good scores mean visitors have a good experience—fast loading, stable pages, responsive interactions. Poor scores mean visitors have a frustrating experience.
3. They Impact Conversions
Websites with good Core Web Vitals convert better. Fast, stable, responsive websites keep visitors engaged and make them more likely to take action. Slow, jumpy, unresponsive websites drive visitors away.
4. They're Especially Important on Mobile
Core Web Vitals are especially important for mobile users, who often have slower connections and less powerful devices. Good Core Web Vitals ensure your site works well on mobile, where most web traffic comes from.
5. They Give You a Competitive Advantage
If your competitors have poor Core Web Vitals and you have good ones, you'll rank higher and provide a better experience. This gives you a competitive advantage.
LCP: Largest Contentful Paint (Loading Speed)
LCP measures how long it takes for the largest content element on your page to appear. In simple terms, it measures how fast your main content loads.
What LCP Actually Measures
When someone visits your website, LCP measures the time from when they start loading the page until the largest content element (usually a large image, video, or text block) becomes visible. This is what users perceive as "page load time."
What Score Do You Need to Pass?
- Pass (Good): 2.5 seconds or less
- Needs Improvement: 2.5 to 4 seconds
- Fail (Poor): More than 4 seconds
To pass LCP, your largest content element must load in 2.5 seconds or less.
What Causes Poor LCP?
Common causes of poor LCP include:
- Slow server response time
- Large, unoptimized images
- Slow hosting
- Too many resources loading at once
- Render-blocking JavaScript or CSS
- Slow network connections
How to Pass LCP
- Optimize Images: Compress images before uploading. Use tools like TinyPNG to reduce file sizes without losing quality.
- Resize Images: Don't upload 4000px wide images if they'll only display at 800px. Resize images to the size they'll actually be displayed.
- Use Faster Hosting: Slow hosting causes slow LCP. Consider upgrading to faster hosting or managed WordPress hosting.
- Enable Lazy Loading: Ensure images below the fold load only when needed, not all at once.
- Remove Unnecessary Elements: Remove large images, videos, or other elements that aren't essential.
- Use a CDN: A Content Delivery Network can help serve your content faster.
- Optimize Server Response: Ensure your server responds quickly (under 600ms is ideal).
CLS: Cumulative Layout Shift (Visual Stability)
CLS measures how much your page content shifts or moves around while the page is loading. In simple terms, it measures how "jumpy" or unstable your page is.
What CLS Actually Measures
Have you ever been reading a webpage when suddenly everything jumps down because an image loads? That's layout shift. CLS measures how much content moves around during page load. A high CLS score means your page is unstable and jumps around a lot.
What Score Do You Need to Pass?
- Pass (Good): 0.1 or less
- Needs Improvement: 0.1 to 0.25
- Fail (Poor): More than 0.25
To pass CLS, your page must have minimal layout shift (0.1 or less).
What Causes Poor CLS?
Common causes of poor CLS include:
- Images without width and height attributes
- Ads or embeds that load and push content around
- Fonts that load and change text size
- Content added dynamically after page load
- Pop-ups or banners that appear and push content down
- Web fonts that cause text to shift when they load
How to Pass CLS
- Add Dimensions to Images: Always include width and height attributes on images. This tells the browser how much space to reserve, preventing content from jumping when images load.
- Reserve Space for Ads: If you have ads, reserve space for them so they don't push content around when they load.
- Use Web Fonts Properly: Ensure fonts are loaded properly to prevent text from changing size after the page loads.
- Avoid Pop-ups on Load: Don't show pop-ups immediately when the page loads. If you must use pop-ups, delay them or make them less intrusive.
- Test Your Site: Load your site and watch for content that jumps around. Identify what's causing the shift and fix it.
- Avoid Dynamic Content: Avoid adding content that changes the page layout after it starts loading.
- Use Placeholders: Use placeholders or skeleton screens for content that loads dynamically.
FID: First Input Delay (Interactivity)
FID measures how long it takes for your website to respond when a user first tries to interact with it—clicking a link, tapping a button, or typing in a form. In simple terms, it measures how "responsive" your site feels.
What FID Actually Measures
FID measures the time from when a user first interacts with your page (clicks, taps, types) until the browser can respond to that interaction. If your site feels "frozen" or unresponsive when users try to interact with it, you have a poor FID score.
What Score Do You Need to Pass?
- Pass (Good): 100 milliseconds or less
- Needs Improvement: 100 to 300 milliseconds
- Fail (Poor): More than 300 milliseconds
To pass FID, your site must respond to user interactions in 100 milliseconds or less.
What Causes Poor FID?
Common causes of poor FID include:
- Too much JavaScript running when the page loads
- JavaScript blocking the browser from responding
- Too many plugins or scripts
- Heavy scripts loading and processing
- Slow server response times
- Large JavaScript bundles
How to Pass FID
- Reduce Plugins: Remove unnecessary plugins. Each plugin adds JavaScript that can slow down your site's responsiveness.
- Update Plugins and Themes: Keep all plugins and themes updated. Updates often include performance improvements.
- Use a Faster Host: Slow hosting can cause poor FID. Consider upgrading to faster hosting.
- Remove Unused Scripts: Remove analytics, chat widgets, or other scripts you're not using. Every script adds overhead.
- Optimize Your Theme: Heavy themes with lots of features can slow down responsiveness. Consider using a lighter, performance-focused theme.
- Limit Third-Party Scripts: Every external script adds to load time and can affect responsiveness. Only use what you need.
- Defer Non-Critical JavaScript: Load non-critical JavaScript after the page has loaded, not during initial load.
How to Check Your Core Web Vitals Scores
Before you can improve your Core Web Vitals, you need to know your current scores. Here's how to check them:
Google PageSpeed Insights (Easiest Method)
The easiest way to check your Core Web Vitals is using Google PageSpeed Insights:
- Go to pagespeed.web.dev
- Enter your website URL
- Click "Analyze"
- View your Core Web Vitals scores
PageSpeed Insights will show you:
- Your LCP, CLS, and FID scores
- Whether each score passes (Good), needs improvement, or fails (Poor)
- Specific recommendations for improvement
- Opportunities to optimize
Google Search Console
If you have Google Search Console set up, you can see Core Web Vitals data there:
- Go to Google Search Console
- Click on "Core Web Vitals" in the left menu
- View your scores and see which pages need improvement
Search Console shows you Core Web Vitals data based on real user visits, which is more accurate than lab testing.
Chrome User Experience Report
The Chrome User Experience Report (CrUX) provides Core Web Vitals data based on real Chrome users. This data is available in Google Search Console and other tools.
What It Means to "Pass" Core Web Vitals
To "pass" Core Web Vitals, you need to meet Google's "Good" threshold for all three metrics:
Passing Requirements
- LCP: 2.5 seconds or less
- CLS: 0.1 or less
- FID: 100 milliseconds or less
You need to pass all three metrics. If you pass LCP and CLS but fail FID, you haven't passed Core Web Vitals. All three must be in the "Good" range.
Why All Three Matter
Each metric measures a different aspect of user experience:
- LCP measures loading speed
- CLS measures visual stability
- FID measures interactivity
All three are important for a good user experience. A fast-loading site that jumps around (good LCP, poor CLS) still provides a poor experience. A stable site that's unresponsive (good CLS, poor FID) also provides a poor experience.
Step-by-Step: How to Pass Core Web Vitals
Here's a step-by-step approach to passing Core Web Vitals:
Step 1: Check Your Current Scores
Use Google PageSpeed Insights to check your current LCP, CLS, and FID scores. Note which metrics are passing and which need improvement.
Step 2: Prioritize Improvements
Focus on the metric with the worst score first. If all three are failing, start with LCP as it often has the biggest impact.
Step 3: Implement Quick Wins
Start with easy improvements that have big impact:
- Compress and optimize images
- Remove unnecessary plugins
- Add dimensions to images
- Remove pop-ups that appear on load
- Update plugins and themes
Step 4: Address Specific Issues
Use PageSpeed Insights recommendations to identify specific issues. Address each recommendation systematically.
Step 5: Test and Measure
After making changes, test again using PageSpeed Insights. Measure improvement and identify remaining issues.
Step 6: Optimize Further
Continue optimizing until all three metrics pass. This may require more advanced optimizations or professional help.
Step 7: Monitor Ongoing
Core Web Vitals can change over time. Regularly check your scores to ensure they stay in the "Good" range.
Quick Wins to Pass Core Web Vitals
Here are quick improvements you can make today to improve your Core Web Vitals scores:
For LCP (Loading Speed)
- Compress all images using TinyPNG or similar tools
- Resize images to the size they'll actually display
- Remove large, unnecessary images
- Enable lazy loading for images below the fold
- Consider upgrading to faster hosting
For CLS (Visual Stability)
- Ensure images have width and height attributes
- Remove or delay pop-ups that appear on page load
- Reserve space for ads and embeds
- Test your site and fix any content that jumps around
For FID (Interactivity)
- Remove unnecessary plugins
- Update all plugins and themes
- Remove unused scripts and widgets
- Consider using a lighter theme
- Limit third-party scripts
Common Mistakes That Prevent Passing
Avoid these common mistakes that prevent websites from passing Core Web Vitals:
1. Ignoring Mobile Scores
Core Web Vitals are especially important on mobile. Many people only check desktop scores, but mobile scores are what Google primarily uses for rankings.
2. Focusing on Only One Metric
You need to pass all three metrics. Don't focus on improving LCP while ignoring CLS and FID.
3. Not Testing After Changes
Always test your Core Web Vitals scores after making changes. Some changes can improve one metric while hurting another.
4. Using Slow Hosting
Slow hosting hurts all Core Web Vitals. Don't try to save money on hosting—it costs more in lost rankings and traffic.
5. Uploading Large Images
Large, unoptimized images are one of the biggest causes of poor Core Web Vitals. Always compress images before uploading.
6. Too Many Plugins
Every plugin adds overhead. Too many plugins slow down your site and hurt Core Web Vitals scores.
7. Not Monitoring Scores
Core Web Vitals can change over time. Regularly check your scores to catch problems early.
How Long Does It Take to Pass Core Web Vitals?
How long it takes to pass Core Web Vitals depends on your starting point and what improvements are needed:
Quick Wins (1-7 Days)
If your scores are close to passing, quick wins like image optimization and removing unnecessary plugins can get you to passing in a few days.
Moderate Improvements (1-4 Weeks)
If your scores need moderate improvement, implementing recommended optimizations typically takes 1-4 weeks, depending on your technical skills and available time.
Major Improvements (1-3 Months)
If your scores are very poor, major improvements like hosting upgrades, theme changes, or code optimization can take 1-3 months.
Ongoing Optimization
Even after passing, you should continue monitoring and optimizing. Core Web Vitals can change as you add content, plugins, or features.
What Happens After You Pass?
Once you pass Core Web Vitals, here's what you can expect:
Better Search Rankings
Passing Core Web Vitals can improve your search rankings, though it's just one of many ranking factors. Don't expect immediate dramatic changes, but you should see gradual improvement.
Better User Experience
Passing Core Web Vitals means your website provides a better user experience. Visitors will have faster, more stable, more responsive experiences.
Higher Conversion Rates
Better user experience typically leads to higher conversion rates. Fast, stable, responsive websites convert better than slow, jumpy, unresponsive ones.
Ongoing Monitoring
You should continue monitoring your Core Web Vitals scores. They can change as you add content, update plugins, or make changes to your site.
When to Seek Professional Help
While many Core Web Vitals improvements can be made yourself, professional help can be valuable when:
- Your scores are very poor and you don't know where to start
- You've tried improvements but scores haven't improved
- You need technical changes (code optimization, server configuration, etc.)
- You don't have time to implement improvements yourself
- You want to ensure improvements are done correctly
- You need ongoing monitoring and optimization
- You want to pass Core Web Vitals quickly
At Webclinic, we specialize in helping websites pass Core Web Vitals. We analyze your current scores, identify what's preventing you from passing, and implement improvements that actually work.
Our Core Web Vitals optimization service includes comprehensive analysis, strategic improvements, testing, and ongoing monitoring. We ensure your website meets Google's Core Web Vitals requirements and stays in the "Good" range.
Ready to pass Core Web Vitals? Book a free website health check with us. We'll analyze your Core Web Vitals scores, identify what's preventing you from passing, and outline a clear plan to get all three metrics into the "Good" range.