Short answer
Core Web Vitals are three Google measures of how a page feels to real visitors. Largest Contentful Paint (LCP) checks loading and is good at 2.5 seconds or less. Interaction to Next Paint (INP) checks how fast the page reacts to taps and clicks and is good at 200 milliseconds or less. Cumulative Layout Shift (CLS) checks visual stability and is good at 0.1 or less.
The three measures and their limits
Anything between good and poor is labelled "needs improvement". INP replaced an older measure, First Input Delay, in March 2024, so older articles may still mention FID.
- LCP, loading: how long until the biggest image or block of text in view has appeared. Good is 2.5 seconds or less. Poor is more than 4 seconds.
- INP, responsiveness: how long the page takes to show a visible reaction after a tap, click or key press. Good is 200 milliseconds or less. Poor is more than 500 milliseconds.
- CLS, visual stability: how much things jump around while the page loads. It is a score, not a time. Good is 0.1 or less. Poor is more than 0.25.
How a page passes
Google does not use your fastest visit or an average. It looks at the experience of most visitors: a page passes a measure when at least three out of every four visits are in the good range. Phone and computer visits are judged separately, and phones are usually slower, so check the phone result first.
Field data and lab data are not the same thing
Field data comes from real Chrome users over the last 28 days and is published in the Chrome UX Report. This is what Google uses. Small sites often have no field data for individual pages because there are not enough visits.
Lab data comes from a single test run in a controlled setting, such as PageSpeed Insights or Lighthouse. It is useful for finding causes and testing fixes, but one lab run can differ from what visitors experience. Lab tests cannot measure INP directly because nobody taps the page, so they show related signals like Total Blocking Time.
Do they affect rankings?
They are part of Google's page experience signals, but relevance comes first. A slow page with the clearest answer can still outrank a fast page with a weak one. Treat Core Web Vitals as a tie-breaker and, more importantly, as a customer experience issue: people leave pages that load slowly or jump about while they try to tap a button.
Where to start if your pages fail
- Fix the measure that is poor before the one that needs improvement.
- Work on templates, not single pages. One fix to a product page template helps every product.
- Check phone results first.
- After a fix, field data takes up to 28 days to fully reflect it, so judge changes over weeks.
How AI Marketing Master shows them
The app shows Core Web Vitals for phone and computer side by side, with Chrome UX Report field data where it exists and PageSpeed Insights lab data for any page. Each result carries a plain status word and a short note on what usually causes the problem. This needs a Google API key that the platform sets up.
What it does not do
- The app reports Core Web Vitals and explains causes. It does not change your code, hosting or images to make pages faster.
- Field data is only available where Google has enough real Chrome visits.
Questions people ask
What is a good Core Web Vitals score?
There is no single score. Each measure passes on its own: LCP at 2.5 seconds or less, INP at 200 milliseconds or less, and CLS at 0.1 or less, for most visits.
Why does PageSpeed Insights show different numbers each time?
Lab tests run once on a simulated device and network, so results vary between runs. Field data from real visitors is steadier and is what Google uses.
My page has no field data. What now?
Use lab data to find problems, and check the origin-level field data for your whole site. Pages with few visits often do not get their own field data.
Do Core Web Vitals matter for AI answers?
There is no public evidence that AI answer tools use them directly. A fast, stable page still helps every visitor who arrives from any source.
We only describe what the product really does today. Results depend on your business, your market and many things no tool controls.