How to Improve Core Web Vitals for Better Rankings
Core Web Vitals measure loading, responsiveness and visual stability. Here's how to check them, what 'good' means, and the fixes that usually make the biggest difference.
Key takeaways
- Core Web Vitals are LCP (loading), INP (responsiveness) and CLS (visual stability). INP replaced FID in March 2024.
- 'Good' thresholds: LCP 2.5 seconds or less, INP 200 milliseconds or less, CLS 0.1 or less, measured at the 75th percentile of real visits.
- Field data from real users (in Search Console) matters more than one-off lab scores.
- Images, render-blocking resources, heavy JavaScript and unsized media cause most problems.
Core Web Vitals are three metrics Google uses to measure real-world user experience. They became part of Google’s page experience signals in 2021, and the responsiveness metric changed in March 2024 when INP replaced FID.
The three metrics
| Metric | Measures | Good | Needs improvement | Poor |
|---|---|---|---|---|
| LCP (Largest Contentful Paint) | How fast the main content loads | ≤ 2.5 s | 2.5–4 s | > 4 s |
| INP (Interaction to Next Paint) | How quickly the page responds to taps and clicks | ≤ 200 ms | 200–500 ms | > 500 ms |
| CLS (Cumulative Layout Shift) | How much the layout jumps around | ≤ 0.1 | 0.1–0.25 | > 0.25 |
Google assesses these at the 75th percentile of real visits, so most of your visitors need a good experience, not just the fast ones.
How to check them
- Search Console → Core Web Vitals: groups of URLs by status, based on real Chrome user data
- PageSpeed Insights: field data (real users) at the top, lab diagnostics below
- Chrome DevTools → Performance: to dig into specific issues
Prioritise field data. Lab scores are a diagnostic tool, not the target.
Fixing LCP (loading)
The LCP element is usually a hero image, a large heading or a banner.
- Compress and resize the hero image; serve WebP or AVIF
- Don’t lazy-load the LCP image; consider
fetchpriority="high" - Reduce server response time (good hosting, page caching, a CDN)
- Remove render-blocking CSS and JavaScript, or inline critical CSS
- Avoid sliders and heavy page builders above the fold
Fixing INP (responsiveness)
Poor INP usually comes from too much JavaScript running when someone interacts.
- Remove unused plugins, tracking scripts and third-party widgets
- Defer non-essential JavaScript
- Break up long tasks; avoid heavy work in click handlers
- Be cautious with chat widgets, pop-ups and complex sliders
Fixing CLS (stability)
- Add
widthandheightto images and videos - Reserve space for ads, embeds and banners
- Use
font-display: swapand preload key fonts - Don’t insert content above existing content after load
What matters most
Core Web Vitals are a tie-breaker-style signal; relevance and helpfulness matter more. But speed affects conversions directly, so it’s worth fixing regardless of rankings. Read how website speed affects SEO and user experience.
Core Web Vitals are part of the technical SEO audit.