Core Web Vitals & Page Speed

Why Speed Matters

Site speed is a confirmed ranking factor, especially for mobile. In 2026, Google uses Core Web Vitals—specific measurements of user experience—to assess page quality. Slow sites frustrate users and directly impact your bottom line.

The Three Core Web Vitals

Google measures three specific aspects of page experience:

• LCP (Largest Contentful Paint): How long the main content takes to load. Target: under 2.5 seconds.
• INP (Interaction to Next Paint): How quickly the site responds when clicked. Target: under 200 milliseconds.
• CLS (Cumulative Layout Shift): How much the page layout shifts during loading. Target: under 0.1.

LCP: Loading Performance

LCP measures when the largest content element (usually an image or hero text) becomes visible. Slow LCP means users are staring at a blank screen.

• Optimize images: compress, use modern formats (WebP), implement lazy loading
• Preload critical resources: hero images, fonts, above-the-fold CSS
• Remove render-blocking move non-critical JS below the fold
• Use a CDN: serve content from servers closer to users

INP: Interactivity

INP measures how quickly your site responds to user input (clicks, taps, typing). Poor INP means users click and nothing happens immediately, which feels broken.

• Reduce JavaScript execution time: split long tasks, code-splitting
• Minimize main thread work: defer non-critical JS
• Use web workers: offload heavy computation to background threads

CLS: Visual Stability

CLS measures how much page elements shift as the page loads. Ever clicked a button just as it moved, causing you to click something else? That's poor CLS.

• Reserve space for images and videos: specify width and height attributes
• Don't inject content above existing content: ads, pop-ups, dynamic content
• Use transform animations instead of changing layout properties