Core Web Vitals: What They Are and How to Fix Them
Core web vitals are Google’s way of measuring how people experience your website. These performance signals look at how quickly a page loads, how responsive it is when someone interacts with it, and whether the layout stays stable while the page appears.
- What Core Web Vitals Are
- The Three Core Web Vitals Metrics (LCP, INP, CLS)
- Common Causes of Poor Core Web Vitals
- Prioritized Fixes to Improve Core Web Vitals
- Tools to Measure Core Web Vitals
A page may contain helpful content, but if it loads slowly or shifts while someone is reading it, visitors often leave before engaging with the site. Improving these performance signals helps create a smoother experience for users and can support stronger search visibility.
Understanding how core web vitals work makes it easier to identify where improvements can be made.
What Are Core Web Vitals?
These metrics focus on three key parts of website performance: loading speed, responsiveness, and visual stability. Google includes them within its broader page experience signals to help evaluate how usable a page feels for real visitors.
The three key metrics are:
- Largest Contentful Paint (LCP)
- Interaction to Next Paint (INP)
- Cumulative Layout Shift (CLS)
Each metric focuses on a different part of the visitor experience. One measures loading speed, another measures responsiveness, and the third evaluates visual stability.
Google groups results into three categories:
- Good
- Needs Improvement
- Poor
Ideally, the most important pages on your site should fall into the Good category for each of these metrics. Monitoring core web vitals regularly helps ensure that your most important pages continue delivering a smooth experience for visitors.
Largest Contentful Paint (LCP): Page Loading Speed
Largest Contentful Paint measures how long it takes for the main visible content on a page to appear. In most cases this is the hero image, main headline, or large content block near the top of the page.
Google considers these thresholds when evaluating performance:
- Good: 2.5 seconds or less
- Needs Improvement: 2.5 to 4 seconds
- Poor: more than 4 seconds
If this content takes too long to appear, visitors may assume the page is slow or broken and leave before exploring the rest of the site.
Common Causes of Slow LCP
Several issues can delay how quickly the main content loads. Large images are one of the most common causes. Oversized hero images or sliders often slow down the loading of the most visible elements on the page.
Other common causes include:
- Slow server response time
- Large page builders or complex layouts
- Scripts loading before the page displays
- Images that are not optimized
- Too many plugins running at once
How to Improve LCP
Improving loading performance often comes down to simplifying what the browser needs to load first.
Start by optimizing images so they are the correct size and compressed properly. You may also want to review whether sliders are necessary. A single optimized hero image usually performs much better.
Additional improvements include:
- Using modern image formats such as WebP
- Enabling page caching
- Reducing heavy scripts or plugins
- Improving hosting performance
- Using a content delivery network (CDN)
These changes can significantly improve loading performance and help strengthen your core web vitals scores.
Interaction to Next Paint (INP): Page Responsiveness
Interaction to Next Paint measures how quickly a page responds when someone interacts with it. This includes actions like clicking a button, opening a menu, or submitting a form.
Google considers the following thresholds:
- Good: under 200 milliseconds
- Needs Improvement: 200 to 500 milliseconds
- Poor: over 500 milliseconds
If a page takes too long to respond after someone clicks or taps something, the website can feel sluggish or unresponsive.
Common Causes of Poor Responsiveness
The most common cause is excessive JavaScript. JavaScript powers many interactive elements on a website, including menus, sliders, forms, and pop-ups. When too many scripts run at once, the browser can struggle to process user interactions quickly.
Other factors include:
- Heavy third-party scripts
- Plugin conflicts
- Complex animations or visual effects
- Overloaded page builders
How to Improve INP
Improving responsiveness usually involves reducing the amount of work the browser must perform.
Start by reviewing the scripts running on your website. Many sites load scripts that are rarely used.
You can also improve responsiveness by:
- Removing unnecessary plugins
- Deferring non-critical JavaScript
- Limiting third-party scripts
- Simplifying interactive features
- Reducing heavy animations
These changes help pages respond more quickly when users interact with them, improving overall core web vitals performance.
Cumulative Layout Shift (CLS): Visual Stability
Cumulative Layout Shift measures how much page elements move while a page is loading.
If you have ever tried to click a link or button and the page suddenly shifted, you have experienced a layout shift. When elements move unexpectedly, it disrupts the reading experience and can cause accidental clicks.
Google evaluates layout stability using these thresholds:
- Good: less than 0.1
- Needs Improvement: 0.1 to 0.25
- Poor: greater than 0.25
Common Causes of Layout Shifts
Many layout shifts happen because the browser does not know how much space to reserve for elements before they load. Images are a common example. If image dimensions are not defined in the code, the browser may leave no space for them initially.
Other causes include:
- Ads or embedded elements loading late
- Fonts loading after the page displays
- Buttons or forms appearing after other content
- Embedded videos or widgets
How to Improve CLS
Reducing layout shifts usually involves defining space for elements before they appear. Helpful improvements include:
- Defining image width and height in the code
- Reserving space for embedded media
- Loading fonts properly
- Avoiding elements that suddenly push content downward
- Ensuring buttons and key elements render quickly
These adjustments help maintain a stable layout while the page loads and support stronger core web vitals scores.
A Checklist to Improve Core Web Vitals
If you are working to improve core web vitals, start with the changes that usually have the biggest impact.
- Optimize large images so they load quickly
- Replace sliders with a single optimized hero image when possible
- Improve server performance through caching or better hosting
- Reduce unnecessary plugins and scripts
- Enable lazy loading for images below the fold
- Use a content delivery network for faster global delivery
After addressing these areas, you can begin refining smaller technical issues that may affect performance.
How to Measure Core Web Vitals
Several tools can help measure core web vitals and identify performance issues on your website.
Google PageSpeed Insights provides both lab data and real-world performance data collected from Chrome users. Google Search Console also includes a dedicated core web vitals report that highlights pages needing improvement.
Why Core Web Vitals Matter for SEO
Google considers page experience as part of how it evaluates websites in search results. Pages that load quickly, respond smoothly, and remain stable while loading provide a better experience for visitors. Strong core web vitals often lead to faster pages, better engagement, and fewer visitors leaving the site prematurely.
Need Help Improving Your Website Performance?
If your website is struggling with slow load times or poor core web vitals scores, it may be time to take a closer look at how your site is built and optimized.
We help businesses identify the technical issues that affect performance and implement practical improvements that make websites faster, more stable, and easier for visitors to use.
If you would like a second set of eyes on your website, reach out and request a performance review. A few focused improvements can often make a noticeable difference in both user experience and search visibility.
