What is Core Web Vitals?CWV
Core Web Vitals (CWV) are a set of three Google metrics — Largest Contentful Paint (LCP), Interaction to Next Paint (INP), and Cumulative Layout Shift (CLS) — that quantify real-user page experience and feed both rankings and conversion.
Core Web Vitals translate user experience into measurable numbers. LCP measures how fast the main content loads (target: under 2.5 seconds). INP measures responsiveness — how quickly the page reacts to interaction (target: under 200ms). CLS measures visual stability — whether content jumps around as the page loads (target: under 0.1). Google uses CWV as a ranking factor and as a critical input to search experience reports. Beyond rankings, CWV are direct correlates of conversion: a 1-second LCP improvement typically lifts conversion 5–15% on commercial pages. Codnity Dev and Creative jointly optimise CWV through framework choice, image strategy, font loading, layout architecture, and runtime monitoring.
What it includes
- LCP optimisation (image priority, server response, render-blocking resources)
- INP optimisation (JavaScript size, main-thread work, hydration strategy)
- CLS optimisation (explicit dimensions, font-display, layout stability)
- Real-user monitoring (CrUX, Search Console, RUM tools)
- Lighthouse and PageSpeed Insights audits
- Framework and rendering strategy choice
How it works
Establish baseline
Pull current CrUX data from Search Console + run Lighthouse on top pages. Identify the 1–2 metrics that fail Google thresholds.
Address by leverage
Image strategy and render path for LCP. Bundle size and hydration for INP. Explicit dimensions for CLS. Highest-impact change first.
Validate in production
Lab tools (Lighthouse) lie on dev builds. Always test production with realistic throttling. Track real-user metrics monthly.
Defend the gains
CWV regress when teams add features without budgets. Set performance budgets and alert when builds break them.
Frequently asked
Are Core Web Vitals a ranking factor?
Yes, but indirectly. Google uses CWV as one of many signals in page experience ranking. The bigger commercial impact is on conversion — fast pages convert measurably better.
What CWV thresholds should I target?
Google considers a page "good" when LCP is under 2.5s, INP under 200ms, and CLS under 0.1 — measured at the 75th percentile of real users. Aim better than that on commercial pages.
How do I monitor CWV continuously?
Search Console reports CrUX field data. Lab tools (Lighthouse, PageSpeed Insights) test specific URLs. Real-user monitoring (RUM) catches issues lab tools miss. Use all three.