A Practical Core Web Vitals Checklist for 2026
LCP, INP, and CLS in plain English, plus the exact fixes I run through to get a site into the green. No fluff.
TLDR: three metrics decide your Core Web Vitals. LCP (loading) under 2.5s, INP (responsiveness) under 200ms, and CLS (visual stability) under 0.1. Most failures come from heavy images, render-blocking scripts, and layout shift from unsized media. Fix those three and you are usually green.
The three metrics, in plain English
- LCP (Largest Contentful Paint): how fast the biggest thing on screen loads. Target under 2.5 seconds.
- INP (Interaction to Next Paint): how quickly the page responds when someone taps or clicks. Target under 200 milliseconds.
- CLS (Cumulative Layout Shift): how much the page jumps around while loading. Target under 0.1.
LCP checklist
- Serve your hero image in a modern format (WebP or AVIF) and size it correctly.
- Preload the LCP image and do not lazy-load it.
- Remove render-blocking CSS and JavaScript from the critical path.
- Use a fast host and a CDN.
- Keep the largest element simple. A giant background video will always be slow.
INP checklist
- Reduce JavaScript. Ship less, defer what you can.
- Break up long tasks so the main thread stays responsive.
- Load heavy third-party scripts after interaction, not on first paint.
- Watch for expensive scroll and input handlers.
CLS checklist
- Set explicit width and height on all images and video.
- Reserve space for ads, embeds, and banners so nothing pushes content down.
- Do not inject content above existing content after load.
- Load fonts with font-display swap and matched fallback metrics to avoid reflow.
How to measure
- Field data: Google Search Console and the Chrome User Experience Report show real users.
- Lab data: Lighthouse and PageSpeed Insights for diagnosing.
- Fix against field data where you have it. Lab data is for finding causes.
The usual culprits
- One oversized hero image.
- A pile of third-party scripts on every page.
- Unsized images causing shift.
- A booking or chat widget loading eagerly on first paint.
FAQ
Do Core Web Vitals affect Google rankings? Yes, page experience is a ranking signal. It rarely outweighs content and links, but for competitive queries it can be the tiebreaker, and it directly affects conversions.
What is a good Core Web Vitals score? Pass all three thresholds for at least 75 percent of real visits: LCP under 2.5s, INP under 200ms, CLS under 0.1.