Core Web Vitals are three Google metrics that measure real-world user experience on a web page: Largest Contentful Paint (LCP) for loading speed, Interaction to Next Paint (INP) for responsiveness, and Cumulative Layout Shift (CLS) for visual stability. Good scores are an LCP of 2.5 seconds or less, an INP of 200 milliseconds or less, and a CLS of 0.1 or less. They are part of Google’s page experience signals and strongly affect conversions.
A slow or jumpy page frustrates visitors and costs sales long before it affects rankings. Core Web Vitals give you a shared, measurable definition of a good experience. This guide explains each metric, how to measure it and how to improve it.
Key Takeaways
- Core Web Vitals measure loading (LCP), responsiveness (INP) and visual stability (CLS).
- INP replaced First Input Delay (FID) as the responsiveness metric in 2024.
- Google evaluates real-user data at the 75th percentile of page loads, on mobile and desktop.
- They are a ranking signal within page experience, but content relevance still matters most.
- Faster, more stable pages almost always convert better.
The Three Core Web Vitals
| Metric | What it measures | Good | Needs improvement | Poor |
|---|---|---|---|---|
| LCP (Largest Contentful Paint) | How quickly the main content loads | 2.5 s or less | 2.5 to 4 s | Over 4 s |
| INP (Interaction to Next Paint) | How quickly the page responds to taps, clicks and key presses | 200 ms or less | 200 to 500 ms | Over 500 ms |
| CLS (Cumulative Layout Shift) | How much content unexpectedly moves while loading | 0.1 or less | 0.1 to 0.25 | Over 0.25 |
How to Measure Core Web Vitals
- Google Search Console: the Core Web Vitals report groups your URLs by status using real-user data.
- PageSpeed Insights: shows field data from the Chrome UX Report plus lab diagnostics and specific fixes.
- Lighthouse and Chrome DevTools: lab testing for debugging during development.
- Real user monitoring: analytics or performance tools that collect metrics from your actual visitors.
Field data (from real users) is what Google uses. Lab data helps you find and fix the causes.
How to Improve Largest Contentful Paint (LCP)
- Use fast, reliable hosting and a content delivery network (CDN). See our managed WordPress hosting.
- Compress and properly size images; serve modern formats such as WebP or AVIF.
- Preload the hero image and do not lazy-load content above the fold.
- Reduce render-blocking CSS and JavaScript; defer what is not needed immediately.
- Use page and object caching to cut server response time.
How to Improve Interaction to Next Paint (INP)
- Reduce and split long JavaScript tasks so the browser can respond quickly.
- Remove unused plugins, tag manager tags and third-party scripts.
- Delay non-essential scripts such as chat widgets until after interaction.
- Keep the DOM lean; very large pages take longer to update.
How to Improve Cumulative Layout Shift (CLS)
- Set width and height (or aspect ratio) on images, videos and embeds.
- Reserve space for ads, banners and dynamic content.
- Load web fonts carefully, using font-display and preloading key fonts.
- Avoid inserting content above existing content unless the user triggers it.
Do Core Web Vitals Affect SEO?
Yes, as part of Google’s page experience signals, but they are not the most important factor. A highly relevant, helpful page can still rank with average scores. Where Core Web Vitals matter most is in close competition and in conversions: faster, more stable pages keep visitors engaged and turn more of them into customers. Learn more about technical and on-page work in our SEO services and in advanced SEO strategies.
Build Speed In From the Start
Retrofitting performance is harder than designing for it. Every website we design is built with lean code, optimized media and Core Web Vitals in mind, then monitored after launch.
Frequently Asked Questions
What are Core Web Vitals?
Core Web Vitals are three Google metrics that measure page experience: Largest Contentful Paint for loading, Interaction to Next Paint for responsiveness and Cumulative Layout Shift for visual stability.
What are good Core Web Vitals scores?
A good score is an LCP of 2.5 seconds or less, an INP of 200 milliseconds or less and a CLS of 0.1 or less, measured at the 75th percentile of real page loads.
What replaced First Input Delay?
Interaction to Next Paint (INP) replaced First Input Delay (FID) as a Core Web Vital in March 2024. INP measures responsiveness across all interactions on a page rather than only the first one.
How do I check my website’s Core Web Vitals?
Use the Core Web Vitals report in Google Search Console for site-wide real-user data, and PageSpeed Insights to test individual pages and get specific recommendations.
Are Core Web Vitals a ranking factor?
Yes. They are part of Google’s page experience signals. Relevance and content quality carry more weight, but strong Core Web Vitals can help in competitive results and improve conversion rates.
