Guide · 5 min read · updated
Core Web Vitals in plain words
LCP, CLS and INP explained without jargon, with the thresholds that count as good and the usual fixes. Run the free website check on your own site.
Core Web Vitals are three measurements of how a page feels to a real person: how fast the main content appears, whether things jump around, and how quickly the page reacts. Search engines use them as one signal among many. Visitors notice them every time.
The three numbers
| Metric | What it measures | Good |
|---|---|---|
| LCP, Largest Contentful Paint | When the biggest thing on screen has loaded | 2.5 seconds or less |
| CLS, Cumulative Layout Shift | How much the layout jumps while loading | 0.1 or less |
| INP, Interaction to Next Paint | How fast the page responds to a tap or click | 200 milliseconds or less |
Lab numbers and field numbers
A lab tool such as Lighthouse loads the page once in a controlled setup and reports LCP and CLS. It cannot measure INP because nobody is tapping; it reports Total Blocking Time as a stand-in. Field data comes from real visits over time. Both are useful. Neither should be invented, which is why our portal shows a dash, not a number, until a real run exists.
Usual fixes
- Slow LCP: a huge hero image. Resize it, serve a modern format, and load it first.
- High CLS: images without set dimensions, late-loading fonts, banners that push content down. Reserve the space.
- Poor INP: heavy scripts, often from third-party widgets and trackers. Remove what you do not need.
How we handle it
Speed is one of the five tests every bytyn project passes before review, alongside mobile, forms, links and titles. After launch, Care clients see Lighthouse runs in the portal. If your current site fails these numbers, Redesign exists for exactly that.