Core Web Vitals
A set of Google metrics measuring real-world page experience: how fast a page loads, how quickly it responds, and how stable it stays while loading.
Definition
Core Web Vitals are three specific metrics Google uses to measure the user experience of a page: loading speed, interactivity, and visual stability. They're part of Google's page experience signals and a confirmed, if minor, ranking factor. More importantly, they directly affect whether visitors stay and convert.
In depth
The three metrics are Largest Contentful Paint (LCP), which measures how quickly the main content loads; Interaction to Next Paint (INP), which measures how fast the page responds when someone interacts with it; and Cumulative Layout Shift (CLS), which measures how much the page jumps around as it loads. Google considers LCP good at 2.5 seconds or less, INP good at 200 milliseconds or less, and CLS good at 0.1 or less. Scores are measured on real visitors, not just lab tests.
These metrics matter because page experience is where SEO and conversion overlap. A slow, janky page frustrates visitors before they ever read your offer, so even if you rank, you bleed leads. Improving Core Web Vitals, through faster hosting, optimized images, cleaner code, and reserved space for elements, lifts both rankings and conversion rate at the same time.
The mistake is chasing a perfect lab score while ignoring the real-user data Google actually uses. WellBuilt prioritizes the field data in Search Console and focuses fixes where they move the needle for visitors, because a fast page that converts beats a flawless test result that no one experiences.
The formula
Good thresholds: LCP at or under 2.5s, INP at or under 200ms, CLS at or under 0.1, measured on real-world traffic. Worked example
A remodeler's project-gallery landing page, slowed to a 5-second LCP by heavy before-and-after photos, gets reworked with compressed images and reserved element space, dropping load time under 2.5 seconds and lifting both rankings and estimate requests.
SEO
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