Core Web Vitals
A set of three Google-defined metrics that measure real-world user experience for loading performance, interactivity, and visual stability. Core Web Vitals are a confirmed ranking factor in Google Search.
Core Web Vitals consist of three metrics: Largest Contentful Paint (loading), Interaction to Next Paint (interactivity), and Cumulative Layout Shift (visual stability). Google uses these metrics as part of its page experience signals to evaluate how users actually experience a web page, not just its content quality.
For growth teams, Core Web Vitals directly impact both search rankings and conversion rates. Pages that pass all three thresholds are eligible for enhanced SERP features and tend to rank better in competitive queries. More importantly, the metrics correlate strongly with business outcomes: every 100ms improvement in LCP can increase conversion rates by up to 1.3%. Monitor Core Web Vitals through Google Search Console and Chrome UX Report data. Focus optimization efforts on the metric with the worst pass rate first, as failing any single vital can impact the overall assessment. Real user monitoring (RUM) data is more valuable than lab tests for understanding actual user experience.
Related Terms
Largest Contentful Paint (LCP)
A Core Web Vital that measures the time from page load start until the largest visible content element (image, video, or text block) is rendered on screen. Good LCP is 2.5 seconds or less.
Interaction to Next Paint (INP)
A Core Web Vital that measures the latency of all user interactions (clicks, taps, keyboard input) throughout the page lifecycle, reporting the worst interaction. Good INP is 200 milliseconds or less.
Cumulative Layout Shift (CLS)
A Core Web Vital that measures the total amount of unexpected layout shifts that occur during a page's entire lifespan. Good CLS is 0.1 or less, where layout shifts are calculated from the impact and distance of moving elements.
Time to First Byte (TTFB)
The duration from the user's request to the first byte of the server response reaching the browser. TTFB measures server-side processing speed and network latency, directly impacting all subsequent loading metrics.
Crawl Budget
The number of pages a search engine bot will crawl on your site within a given timeframe, determined by crawl rate limit and crawl demand. Crawl budget optimization ensures important pages are discovered and indexed efficiently.
Canonical URL
An HTML element that tells search engines which version of a page is the preferred one when multiple URLs serve similar or identical content. Canonical tags consolidate ranking signals and prevent duplicate content issues.