Metrics

What each number means and how to improve it.

• LCPCore Web VitalLargest Contentful PaintWhen the main content, usually the hero image or headline, finishes loading.Good: 2.5 s or less
• INPCore Web VitalInteraction to Next PaintHow fast the page reacts when someone clicks, taps or types.Good: 200 ms or less
• CLSCore Web VitalCumulative Layout ShiftHow much the layout jumps while the page loads.Good: 0.1 or less
• FCPFirst Contentful PaintWhen the first text or image appears on screen.Good: 1.8 s or less
• TTFBTime to First ByteHow long the browser waits for the server to start responding.Good: 800 ms or less
• TBTTotal Blocking TimeHow long JavaScript blocked the page from responding during load.Good: 200 ms or less
• SISpeed IndexHow quickly the visible part of the page fills in.Good: 3.4 s or less on mobile